docs: Add RAS framework documentation
Change-Id: Ibf2b21b12ebc0af5815fc6643532a3be9100bf02
Signed-off-by: Jeenu Viswambharan <jeenu.viswambharan@arm.com>
diff --git a/docs/draw.io/ras.svg b/docs/draw.io/ras.svg
new file mode 100644
index 0000000..ff58198
--- /dev/null
+++ b/docs/draw.io/ras.svg
@@ -0,0 +1,2 @@
+<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
+<svg xmlns="http://www.w3.org/2000/svg" style="background-color: rgb(255, 255, 255);" xmlns:xlink="http://www.w3.org/1999/xlink" version="1.1" width="1050px" height="392px" viewBox="-0.5 -0.5 1050 392" content="<mxfile userAgent="Mozilla/5.0 (X11; Linux x86_64; rv:63.0) Gecko/20100101 Firefox/63.0" version="9.4.6" editor="www.draw.io" type="device"><diagram id="f2d74f7d-2b47-d0f0-3260-3a0b726db48c" name="Page-1">5VtLc6M4EP41rto9rAs9eB2TjD0zVbtVqclhd05TipFtNhhRQk7i/fUrQGBAECsJYGcml0Ajgfi6++tWN56hm93zZ06S7V8soNEMWsHzDH2aQQgtx5H/MsmhkABgeYVkw8NAyY6Cu/A/qoSWku7DgKaNgYKxSIRJU7hicUxXoiEjnLOn5rA1i5pPTciGaoK7FYl06d9hILblazj+8cIXGm626tEedIsL92T1sOFsH6vnzSBa53/F5R0p76VeNN2SgD3VRGgxQzecMVEc7Z5vaJSBW8JWzFv2XK3WzWksjCaoGY8k2tNyyfnCxKEEI38dmk2wZuj6aRsKepeQVXb1SepfyrZiF8kzIA9TwdlDBZp8n+t1GEU3LGJcnscsltOuA5Ju8xtmM/Qll2uiXNDnmki9wmfKdlTwgxyirmKs4CztrYT36ag8WI7Z1vSGHCUkymA21b2PoMkDhVsPhug0hjSQ9qVOGRdbtmExiRZH6XUT5Rqi/1IhDspFyF4wKTre4U/Gkl7ke5FN2Z6v1MrUWgXhG1qiUoiyNb+IPqcREeFj02e6kFRTb1koF1JpDcGW1ryWMoo1qVktfVTLMFIRxh0qciKR2WL4KA83IserEN3ztkTevzFuOO2m8iXFVUZZUrCKSJqGq1K8DKNyGI2DcpDyISlR163JjGRsi2i78XgGATV7SOTKf1DyY0viIKL8t9/H5EEZFj7hBVjaw/AfaHuSo/NfNabOf3gA+kMGIWQoB1G2X/eOCawf6RRZDhvOI4zh1tDmJP2ohos9A8N1RjJcaH/kuI07jHJwmjaFUg+vmVFKmqac7xMxmW0ulwvb98exTeT7c3s668R6iDpD3vF2Iz6VsRgZuT1N3oH8uef6wIPAdgCSim4oHgNnXq5k+ExEJ6HF84omImSxFH/JHCeMN/JwycmOPjH+MJUPFSNrV6z8b6CUBTQx97yms3UFAsuaWxC7HgLYxbbvIt3zAIBzu1/9ps7nGPheFIVJSk8DTtKkKFGsw+dMSa8hfHM8oY3mwIE+9oGPbey6TgtPt7LhRlJYotUAcRAM3en4651poUSdH/5Rk/KT79nJ3DagsTdGb1uP3s65gje41DzoJb0YoezrKONRIoo0EXKoDUiywJD2Bxzc2rBhG9Y1dnp8s6wnD4oVvDUI+R0WoJVHvl3d9dVDtLEJDxkPRYZJRB/z8rDKAd9cZHlVlHs5ptWNbNQoJ2829yGq4hxuadHryigNwpw9RNnSugi3f8nJX0GudR/3p8kaoY/mjpur0cUetkHLpUE7ivYkja8lD+i0NyatGv+J8TI96CeP009rF+UKwh2kKNdFQ8NZZKPrkJ3cEiE3qHEugRZ8V6wy3E8ZhS3g6TYNBjdq44LTuDxxAfW9LrzPV+ArV1PDO4+8FpUg8fyJK8aD9H0BctJSiguaHFIVSCYp83X1fi4rvVU7jTL2GdttR35bvtzYwc/1W0GlrarhKiRADwuFQ1T1xXSWt/3J4QP7BOroWY/nEzqnF5Cue4tM8rVEF1yt1n5Ht59E4SYLsiua6UsKMpDCFYmu1IVdGARRXyWlqcEBgG/XdX1D3OEAuCOTwtJAGc4FBNau5BwNXtM1NvquRmWx9QzLXedXaaFE0OxJcZC9IGf3tLZBDYfZnk7aZGszzaRNNtRR31Z5TFUQGA9JZfYDgOibtNhHA1FPCX9q2oAdtOGejTbgadq4DtOsxl+yRsTYwz45A22MmqBM2/9Eev/gpyCOqWEcd/czLluYfSfa+FSngzrKDfUZSic6ddwtvuVajhLKx97Cj/mlzqRbeGRQGHxze6CyWvPOwNDfL7/cJkCup0M9UZMA6xvFXwl5eEbkuz4MycrVJBt1dS8pVNPEZezRh9ZRqwEBbJ15ur7tH2K/jrv261qz82tZhzLsZP6carJbX5z4eDo16bliTSfWbdWM/iUUkX3OZjd10RGsR9PFhE28KfaqrazxLb+nsV9U1x/WHMCmvkqGe2eN3sa4ZQie39JwT/NWu5UD27eyDQv+r+1uA7c70exb2Ynxfd3tcjlsvU7pu7/h1LOkxZdlFqZvv+pJ/sWyjkYxHcbea8bAhU09uKNxjjw9/kKyUNfxd6ho8T8=</diagram></mxfile>"><defs/><rect x="408" y="30" width="240" height="360" fill="none" stroke="#000000" stroke-width="2" stroke-dasharray="6 6" pointer-events="none"/><path d="M 208 90 L 439.76 90" fill="none" stroke="#000000" stroke-width="2" stroke-miterlimit="10" pointer-events="none"/><path d="M 445.76 90 L 437.76 94 L 439.76 90 L 437.76 86 Z" fill="#000000" stroke="#000000" stroke-width="2" stroke-miterlimit="10" pointer-events="none"/><path d="M 79.76 90 L 8 90" fill="none" stroke="#000000" stroke-width="2" stroke-miterlimit="10" pointer-events="none"/><path d="M 85.76 90 L 77.76 94 L 79.76 90 L 77.76 86 Z" fill="#000000" stroke="#000000" stroke-width="2" stroke-miterlimit="10" pointer-events="none"/><g transform="translate(47.5,84.5)"><switch><foreignObject style="overflow:visible;" pointer-events="all" width="1" height="11" requiredFeatures="http://www.w3.org/TR/SVG11/feature#Extensibility"><div xmlns="http://www.w3.org/1999/xhtml" style="display: inline-block; font-size: 11px; font-family: Helvetica; color: rgb(0, 0, 0); line-height: 1.2; vertical-align: top; white-space: nowrap; text-align: center;"><div xmlns="http://www.w3.org/1999/xhtml" style="display:inline-block;text-align:inherit;text-decoration:inherit;background-color:#ffffff;"><div><br /></div></div></div></foreignObject><text x="0" y="11" fill="#000000" text-anchor="middle" font-size="11px" font-family="Helvetica"><div><br></div></text></switch></g><rect x="88" y="70" width="120" height="40" fill="#d4e1f5" stroke="#000000" stroke-width="2" pointer-events="none"/><g transform="translate(98.5,83.5)"><switch><foreignObject style="overflow:visible;" pointer-events="all" width="98" height="12" requiredFeatures="http://www.w3.org/TR/SVG11/feature#Extensibility"><div xmlns="http://www.w3.org/1999/xhtml" style="display: inline-block; font-size: 12px; font-family: Helvetica; color: rgb(0, 0, 0); line-height: 1.2; vertical-align: top; width: 99px; white-space: nowrap; overflow-wrap: normal; text-align: center;"><div xmlns="http://www.w3.org/1999/xhtml" style="display:inline-block;text-align:inherit;text-decoration:inherit;">plat_ea_handler()</div></div></foreignObject><text x="49" y="12" fill="#000000" text-anchor="middle" font-size="12px" font-family="Helvetica">plat_ea_handler()</text></switch></g><path d="M 608 90 L 669.76 90" fill="none" stroke="#000000" stroke-width="2" stroke-miterlimit="10" pointer-events="none"/><path d="M 675.76 90 L 667.76 94 L 669.76 90 L 667.76 86 Z" fill="#000000" stroke="#000000" stroke-width="2" stroke-miterlimit="10" pointer-events="none"/><rect x="448" y="70" width="160" height="40" fill="#d4e1f5" stroke="#000000" stroke-width="2" pointer-events="none"/><g transform="translate(479.5,83.5)"><switch><foreignObject style="overflow:visible;" pointer-events="all" width="95" height="12" requiredFeatures="http://www.w3.org/TR/SVG11/feature#Extensibility"><div xmlns="http://www.w3.org/1999/xhtml" style="display: inline-block; font-size: 12px; font-family: Helvetica; color: rgb(0, 0, 0); line-height: 1.2; vertical-align: top; width: 96px; white-space: nowrap; overflow-wrap: normal; text-align: center;"><div xmlns="http://www.w3.org/1999/xhtml" style="display:inline-block;text-align:inherit;text-decoration:inherit;">ras_ea_handler()</div></div></foreignObject><text x="48" y="12" fill="#000000" text-anchor="middle" font-size="12px" font-family="Helvetica">ras_ea_handler()</text></switch></g><path d="M 608 329.5 L 669.76 329.5" fill="none" stroke="#000000" stroke-width="2" stroke-miterlimit="10" pointer-events="none"/><path d="M 675.76 329.5 L 667.76 333.5 L 669.76 329.5 L 667.76 325.5 Z" fill="#000000" stroke="#000000" stroke-width="2" stroke-miterlimit="10" pointer-events="none"/><rect x="448" y="309.5" width="160" height="40" fill="#ffe599" stroke="#000000" stroke-width="2" pointer-events="none"/><g transform="translate(464.5,322.5)"><switch><foreignObject style="overflow:visible;" pointer-events="all" width="126" height="12" requiredFeatures="http://www.w3.org/TR/SVG11/feature#Extensibility"><div xmlns="http://www.w3.org/1999/xhtml" style="display: inline-block; font-size: 12px; font-family: Helvetica; color: rgb(0, 0, 0); line-height: 1.2; vertical-align: top; width: 127px; white-space: nowrap; overflow-wrap: normal; text-align: center;"><div xmlns="http://www.w3.org/1999/xhtml" style="display:inline-block;text-align:inherit;text-decoration:inherit;">ras_interrupt_handler()</div></div></foreignObject><text x="63" y="12" fill="#000000" text-anchor="middle" font-size="12px" font-family="Helvetica">ras_interrupt_handler()</text></switch></g><path d="M 79.64 326 L 48 326 L 7.88 326.25" fill="none" stroke="#000000" stroke-width="2" stroke-miterlimit="10" pointer-events="none"/><path d="M 85.64 326 L 77.64 330 L 79.64 326 L 77.64 322 Z" fill="#000000" stroke="#000000" stroke-width="2" stroke-miterlimit="10" pointer-events="none"/><rect x="87.88" y="270" width="100.02" height="112.5" fill="#ffe599" stroke="#000000" stroke-width="2" pointer-events="none"/><g transform="translate(89.5,304.5)"><switch><foreignObject style="overflow:visible;" pointer-events="all" width="95" height="41" requiredFeatures="http://www.w3.org/TR/SVG11/feature#Extensibility"><div xmlns="http://www.w3.org/1999/xhtml" style="display: inline-block; font-size: 12px; font-family: Helvetica; color: rgb(0, 0, 0); line-height: 1.2; vertical-align: top; width: 95px; white-space: normal; overflow-wrap: normal; text-align: center;"><div xmlns="http://www.w3.org/1999/xhtml" style="display:inline-block;text-align:inherit;text-decoration:inherit;">Exception Handling Framework</div></div></foreignObject><text x="48" y="27" fill="#000000" text-anchor="middle" font-size="12px" font-family="Helvetica">Exception Handling Framework</text></switch></g><ellipse cx="227" cy="284" rx="6.25" ry="6.25" fill="#ffffff" stroke="#000000" stroke-width="2" pointer-events="none"/><path d="M 187.9 326 L 208 326 L 208 284 L 221 284" fill="none" stroke="#000000" stroke-width="2" stroke-miterlimit="10" pointer-events="none"/><path d="M 368.95 362 L 388 362 L 388 330 L 439.76 330" fill="none" stroke="#000000" stroke-width="2" stroke-miterlimit="10" pointer-events="none"/><path d="M 445.76 330 L 437.76 334 L 439.76 330 L 437.76 326 Z" fill="#000000" stroke="#000000" stroke-width="2" stroke-miterlimit="10" pointer-events="none"/><rect x="268.92" y="338.5" width="100.02" height="50" fill="#ffe599" stroke="#000000" stroke-width="2" pointer-events="none"/><g transform="translate(270.5,342.5)"><switch><foreignObject style="overflow:visible;" pointer-events="all" width="95" height="41" requiredFeatures="http://www.w3.org/TR/SVG11/feature#Extensibility"><div xmlns="http://www.w3.org/1999/xhtml" style="display: inline-block; font-size: 12px; font-family: Helvetica; color: rgb(0, 0, 0); line-height: 1.2; vertical-align: top; width: 95px; white-space: normal; overflow-wrap: normal; text-align: center;"><div xmlns="http://www.w3.org/1999/xhtml" style="display:inline-block;text-align:inherit;text-decoration:inherit;"><div>RAS</div><div>priority level handler<br /></div></div></div></foreignObject><text x="48" y="27" fill="#000000" text-anchor="middle" font-size="12px" font-family="Helvetica">[Not supported by viewer]</text></switch></g><path d="M 228 290 L 228 300 L 228 364 L 260.76 364" fill="none" stroke="#000000" stroke-width="2" stroke-miterlimit="10" pointer-events="none"/><path d="M 266.76 364 L 258.76 368 L 260.76 364 L 258.76 360 Z" fill="#000000" stroke="#000000" stroke-width="2" stroke-miterlimit="10" pointer-events="none"/><path d="M 758 198.24 L 758 221.76" fill="none" stroke="#000000" stroke-width="2" stroke-miterlimit="10" stroke-dasharray="2 4" pointer-events="none"/><path d="M 758 192.24 L 762 200.24 L 758 198.24 L 754 200.24 Z" fill="#000000" stroke="#000000" stroke-width="2" stroke-miterlimit="10" pointer-events="none"/><path d="M 758 227.76 L 754 219.76 L 758 221.76 L 762 219.76 Z" fill="#000000" stroke="#000000" stroke-width="2" stroke-miterlimit="10" pointer-events="none"/><path d="M 758 150 L 758 118.24" fill="none" stroke="#000000" stroke-width="2" stroke-miterlimit="10" pointer-events="none"/><path d="M 758 112.24 L 762 120.24 L 758 118.24 L 754 120.24 Z" fill="#000000" stroke="#000000" stroke-width="2" stroke-miterlimit="10" pointer-events="none"/><rect x="678" y="150" width="160" height="40" fill="#ffe599" stroke="#000000" stroke-width="2" pointer-events="none"/><g transform="translate(708.5,163.5)"><switch><foreignObject style="overflow:visible;" pointer-events="all" width="98" height="12" requiredFeatures="http://www.w3.org/TR/SVG11/feature#Extensibility"><div xmlns="http://www.w3.org/1999/xhtml" style="display: inline-block; font-size: 12px; font-family: Helvetica; color: rgb(0, 0, 0); line-height: 1.2; vertical-align: top; width: 99px; white-space: nowrap; overflow-wrap: normal; text-align: center;"><div xmlns="http://www.w3.org/1999/xhtml" style="display:inline-block;text-align:inherit;text-decoration:inherit;">RAS error records</div></div></foreignObject><text x="49" y="12" fill="#000000" text-anchor="middle" font-size="12px" font-family="Helvetica">RAS error records</text></switch></g><path d="M 758 270 L 758 290 L 758 301.76" fill="none" stroke="#000000" stroke-width="2" stroke-miterlimit="10" pointer-events="none"/><path d="M 758 307.76 L 754 299.76 L 758 301.76 L 762 299.76 Z" fill="#000000" stroke="#000000" stroke-width="2" stroke-miterlimit="10" pointer-events="none"/><rect x="678" y="230" width="160" height="40" fill="#ffe599" stroke="#000000" stroke-width="2" pointer-events="none"/><g transform="translate(702.5,243.5)"><switch><foreignObject style="overflow:visible;" pointer-events="all" width="110" height="12" requiredFeatures="http://www.w3.org/TR/SVG11/feature#Extensibility"><div xmlns="http://www.w3.org/1999/xhtml" style="display: inline-block; font-size: 12px; font-family: Helvetica; color: rgb(0, 0, 0); line-height: 1.2; vertical-align: top; width: 111px; white-space: nowrap; overflow-wrap: normal; text-align: center;"><div xmlns="http://www.w3.org/1999/xhtml" style="display:inline-block;text-align:inherit;text-decoration:inherit;">RAS interrupts array</div></div></foreignObject><text x="55" y="12" fill="#000000" text-anchor="middle" font-size="12px" font-family="Helvetica">RAS interrupts array</text></switch></g><g transform="translate(485.5,3.5)"><switch><foreignObject style="overflow:visible;" pointer-events="all" width="85" height="12" requiredFeatures="http://www.w3.org/TR/SVG11/feature#Extensibility"><div xmlns="http://www.w3.org/1999/xhtml" style="display: inline-block; font-size: 12px; font-family: Helvetica; color: rgb(0, 0, 0); line-height: 1.2; vertical-align: top; width: 86px; white-space: nowrap; overflow-wrap: normal; text-align: center;"><div xmlns="http://www.w3.org/1999/xhtml" style="display:inline-block;text-align:inherit;text-decoration:inherit;">RAS framework</div></div></foreignObject><text x="43" y="12" fill="#000000" text-anchor="middle" font-size="12px" font-family="Helvetica">RAS framework</text></switch></g><path d="M 838 90 L 879.76 90" fill="none" stroke="#000000" stroke-width="2" stroke-miterlimit="10" stroke-dasharray="6 6" pointer-events="none"/><path d="M 885.76 90 L 877.76 94 L 879.76 90 L 877.76 86 Z" fill="#000000" stroke="#000000" stroke-width="2" stroke-miterlimit="10" pointer-events="none"/><rect x="678" y="70" width="160" height="40" fill="#d4e1f5" stroke="#000000" stroke-width="2" pointer-events="none"/><g transform="translate(710.5,83.5)"><switch><foreignObject style="overflow:visible;" pointer-events="all" width="93" height="12" requiredFeatures="http://www.w3.org/TR/SVG11/feature#Extensibility"><div xmlns="http://www.w3.org/1999/xhtml" style="display: inline-block; font-size: 12px; font-family: Helvetica; color: rgb(0, 0, 0); line-height: 1.2; vertical-align: top; width: 94px; white-space: nowrap; overflow-wrap: normal; text-align: center;"><div xmlns="http://www.w3.org/1999/xhtml" style="display:inline-block;text-align:inherit;text-decoration:inherit;"><i>Iterate and probe</i></div></div></foreignObject><text x="47" y="12" fill="#000000" text-anchor="middle" font-size="12px" font-family="Helvetica"><i>Iterate and probe</i></text></switch></g><rect x="888" y="70" width="160" height="40" fill="none" stroke="#000000" stroke-width="2" pointer-events="none"/><g transform="translate(931.5,83.5)"><switch><foreignObject style="overflow:visible;" pointer-events="all" width="72" height="12" requiredFeatures="http://www.w3.org/TR/SVG11/feature#Extensibility"><div xmlns="http://www.w3.org/1999/xhtml" style="display: inline-block; font-size: 12px; font-family: Helvetica; color: rgb(0, 0, 0); line-height: 1.2; vertical-align: top; width: 73px; white-space: nowrap; overflow-wrap: normal; text-align: center;"><div xmlns="http://www.w3.org/1999/xhtml" style="display:inline-block;text-align:inherit;text-decoration:inherit;">Error handler</div></div></foreignObject><text x="36" y="12" fill="#000000" text-anchor="middle" font-size="12px" font-family="Helvetica">Error handler</text></switch></g><path d="M 838 329.5 L 879.76 329.5" fill="none" stroke="#000000" stroke-width="2" stroke-miterlimit="10" stroke-dasharray="6 6" pointer-events="none"/><path d="M 885.76 329.5 L 877.76 333.5 L 879.76 329.5 L 877.76 325.5 Z" fill="#000000" stroke="#000000" stroke-width="2" stroke-miterlimit="10" pointer-events="none"/><rect x="678" y="309.5" width="160" height="40" fill="#ffe599" stroke="#000000" stroke-width="2" pointer-events="none"/><g transform="translate(708.5,322.5)"><switch><foreignObject style="overflow:visible;" pointer-events="all" width="97" height="12" requiredFeatures="http://www.w3.org/TR/SVG11/feature#Extensibility"><div xmlns="http://www.w3.org/1999/xhtml" style="display: inline-block; font-size: 12px; font-family: Helvetica; color: rgb(0, 0, 0); line-height: 1.2; vertical-align: top; width: 98px; white-space: nowrap; overflow-wrap: normal; text-align: center;"><div xmlns="http://www.w3.org/1999/xhtml" style="display:inline-block;text-align:inherit;text-decoration:inherit;"><i>Bisect and lookup</i></div></div></foreignObject><text x="49" y="12" fill="#000000" text-anchor="middle" font-size="12px" font-family="Helvetica"><i>Bisect and lookup</i></text></switch></g><rect x="888" y="309.5" width="160" height="40" fill="none" stroke="#000000" stroke-width="2" pointer-events="none"/><g transform="translate(931.5,322.5)"><switch><foreignObject style="overflow:visible;" pointer-events="all" width="72" height="12" requiredFeatures="http://www.w3.org/TR/SVG11/feature#Extensibility"><div xmlns="http://www.w3.org/1999/xhtml" style="display: inline-block; font-size: 12px; font-family: Helvetica; color: rgb(0, 0, 0); line-height: 1.2; vertical-align: top; width: 73px; white-space: nowrap; overflow-wrap: normal; text-align: center;"><div xmlns="http://www.w3.org/1999/xhtml" style="display:inline-block;text-align:inherit;text-decoration:inherit;">Error handler</div></div></foreignObject><text x="36" y="12" fill="#000000" text-anchor="middle" font-size="12px" font-family="Helvetica">Error handler</text></switch></g><path d="M 608 170 L 669.76 170" fill="none" stroke="#000000" stroke-width="2" stroke-miterlimit="10" stroke-dasharray="6 6" pointer-events="none"/><path d="M 675.76 170 L 667.76 174 L 669.76 170 L 667.76 166 Z" fill="#000000" stroke="#000000" stroke-width="2" stroke-miterlimit="10" pointer-events="none"/><rect x="448" y="150" width="160" height="40" fill="#d4e1f5" stroke="#000000" stroke-width="2" pointer-events="none"/><g transform="translate(492.5,163.5)"><switch><foreignObject style="overflow:visible;" pointer-events="all" width="69" height="12" requiredFeatures="http://www.w3.org/TR/SVG11/feature#Extensibility"><div xmlns="http://www.w3.org/1999/xhtml" style="display: inline-block; font-size: 12px; font-family: Helvetica; color: rgb(0, 0, 0); line-height: 1.2; vertical-align: top; width: 70px; white-space: nowrap; overflow-wrap: normal; text-align: center;"><div xmlns="http://www.w3.org/1999/xhtml" style="display:inline-block;text-align:inherit;text-decoration:inherit;">SER helpers</div></div></foreignObject><text x="35" y="12" fill="#000000" text-anchor="middle" font-size="12px" font-family="Helvetica">SER helpers</text></switch></g><rect x="268.92" y="288" width="100.02" height="50" fill="none" stroke="#000000" stroke-width="2" stroke-dasharray="6 6" pointer-events="none"/><rect x="268.92" y="238" width="100.02" height="50" fill="none" stroke="#000000" stroke-width="2" stroke-dasharray="6 6" pointer-events="none"/><g transform="translate(24.5,56.5)"><switch><foreignObject style="overflow:visible;" pointer-events="all" width="46" height="27" requiredFeatures="http://www.w3.org/TR/SVG11/feature#Extensibility"><div xmlns="http://www.w3.org/1999/xhtml" style="display: inline-block; font-size: 12px; font-family: Helvetica; color: rgb(0, 0, 0); line-height: 1.2; vertical-align: top; width: 46px; white-space: normal; overflow-wrap: normal; text-align: center;"><div xmlns="http://www.w3.org/1999/xhtml" style="display:inline-block;text-align:inherit;text-decoration:inherit;">External Abort</div></div></foreignObject><text x="23" y="20" fill="#000000" text-anchor="middle" font-size="12px" font-family="Helvetica">External Abort</text></switch></g><g transform="translate(21.5,307.5)"><switch><foreignObject style="overflow:visible;" pointer-events="all" width="45" height="12" requiredFeatures="http://www.w3.org/TR/SVG11/feature#Extensibility"><div xmlns="http://www.w3.org/1999/xhtml" style="display: inline-block; font-size: 12px; font-family: Helvetica; color: rgb(0, 0, 0); line-height: 1.2; vertical-align: top; width: 46px; white-space: nowrap; overflow-wrap: normal; text-align: center;"><div xmlns="http://www.w3.org/1999/xhtml" style="display:inline-block;text-align:inherit;text-decoration:inherit;"><div>Interrupt</div></div></div></foreignObject><text x="23" y="12" fill="#000000" text-anchor="middle" font-size="12px" font-family="Helvetica">[Not supported by viewer]</text></switch></g><g transform="translate(204.5,246.5)"><switch><foreignObject style="overflow:visible;" pointer-events="all" width="46" height="27" requiredFeatures="http://www.w3.org/TR/SVG11/feature#Extensibility"><div xmlns="http://www.w3.org/1999/xhtml" style="display: inline-block; font-size: 12px; font-family: Helvetica; color: rgb(0, 0, 0); line-height: 1.2; vertical-align: top; width: 46px; white-space: normal; overflow-wrap: normal; text-align: center;"><div xmlns="http://www.w3.org/1999/xhtml" style="display:inline-block;text-align:inherit;text-decoration:inherit;">Interrupt Priority</div></div></foreignObject><text x="23" y="20" fill="#000000" text-anchor="middle" font-size="12px" font-family="Helvetica">Interrupt Priority</text></switch></g><path d="M 138 110 L 138 150 L 138 261.76" fill="none" stroke="#000000" stroke-width="2" stroke-miterlimit="10" stroke-dasharray="6 6" pointer-events="none"/><path d="M 138 267.76 L 134 259.76 L 138 261.76 L 142 259.76 Z" fill="#000000" stroke="#000000" stroke-width="2" stroke-miterlimit="10" pointer-events="none"/><g transform="translate(140.5,176.5)"><switch><foreignObject style="overflow:visible;" pointer-events="all" width="38" height="27" requiredFeatures="http://www.w3.org/TR/SVG11/feature#Extensibility"><div xmlns="http://www.w3.org/1999/xhtml" style="display: inline-block; font-size: 12px; font-family: Helvetica; color: rgb(0, 0, 0); line-height: 1.2; vertical-align: top; width: 38px; white-space: normal; overflow-wrap: normal; text-align: center;"><div xmlns="http://www.w3.org/1999/xhtml" style="display:inline-block;text-align:inherit;text-decoration:inherit;">EHF APIs</div></div></foreignObject><text x="19" y="20" fill="#000000" text-anchor="middle" font-size="12px" font-family="Helvetica">EHF APIs</text></switch></g></svg>
\ No newline at end of file
diff --git a/docs/draw.io/ras.xml b/docs/draw.io/ras.xml
new file mode 100644
index 0000000..ce6df3a
--- /dev/null
+++ b/docs/draw.io/ras.xml
@@ -0,0 +1 @@
+<mxfile userAgent="Mozilla/5.0 (X11; Linux x86_64; rv:63.0) Gecko/20100101 Firefox/63.0" version="9.4.6" editor="www.draw.io" type="device"><diagram id="f2d74f7d-2b47-d0f0-3260-3a0b726db48c" name="Page-1">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</diagram></mxfile>
\ No newline at end of file
diff --git a/docs/porting-guide.rst b/docs/porting-guide.rst
index bef4af6..4f1638a 100644
--- a/docs/porting-guide.rst
+++ b/docs/porting-guide.rst
@@ -2646,8 +2646,8 @@
If you're trying to debug crashes in BL1, you can call the console_xx_core_flush
function exported by some console drivers from here.
-Extternal Abort handling and RAS Support
-----------------------------------------
+External Abort handling and RAS Support
+---------------------------------------
Function : plat_ea_handler
~~~~~~~~~~~~~~~~~~~~~~~~~~
diff --git a/docs/ras.rst b/docs/ras.rst
new file mode 100644
index 0000000..4c82022
--- /dev/null
+++ b/docs/ras.rst
@@ -0,0 +1,258 @@
+RAS support in Trusted Firmware-A
+=================================
+
+.. section-numbering::
+ :suffix: .
+
+.. contents::
+ :depth: 2
+
+.. |EHF| replace:: Exception Handling Framework
+.. |TF-A| replace:: Trusted Firmware-A
+
+This document describes |TF-A| support for Arm Reliability, Availability, and
+Serviceability (RAS) extensions. RAS is a mandatory extension for Armv8.2 and
+later CPUs, and also an optional extension to the base Armv8.0 architecture.
+
+In conjunction with the |EHF|, support for RAS extension enables firmware-first
+paradigm for handling platform errors, in which exceptions resulting from
+errors—viz. Synchronous External Abort (SEA), Asynchronous External Abort
+(signalled as SErrors), Fault Handling and Error Recovery interrupts are routed
+to and handled in EL3. The |EHF| document mentions various `error handling
+use-cases`__.
+
+.. __: exception-handling.rst#delegation-use-cases
+
+For the description of Arm RAS extensions, Standard Error Records, and the
+precise definition of RAS terminology, please refer to the Arm Architecture
+Reference Manual. The rest of this document assumes familiarity with
+architecture and terminology.
+
+Overview
+--------
+
+As mentioned above, the RAS support in |TF-A| enables routing to and handling of
+exceptions resulting from platform errors in EL3. It allows the platform to
+define an External Abort handler, and to register RAS nodes and interrupts. RAS
+framework also provides `helpers`__ for accessing Standard Error Records as
+introduced by the RAS extensions.
+
+.. __: `Standard Error Record helpers`_
+
+The build option ``RAS_EXTENSION`` when set to ``1`` includes the RAS in run
+time firmware; ``EL3_EXCEPTION_HANDLING`` and ``HANDLE_EA_EL3_FIRST`` must also
+be set ``1``.
+
+.. _ras-figure:
+
+.. image:: draw.io/ras.svg
+
+See more on `Engaging the RAS framework`_.
+
+Platform APIs
+-------------
+
+The RAS framework allows the platform to define handlers for External Abort,
+Uncontainable Errors, Double Fault, and errors rising from EL3 execution. Please
+refer to the porting guide for the `RAS platform API descriptions`__.
+
+.. __: porting-guide.rst#external-abort-handling-and-ras-support
+
+Registering RAS error records
+-----------------------------
+
+RAS nodes are components in the system capable of signalling errors to PEs
+through one one of the notification mechanisms—SEAs, SErrors, or interrupts. RAS
+nodes contain one or more error records, which are registers through which the
+nodes advertise various properties of the signalled error. Arm recommends that
+error records are implemented in the Standard Error Record format. The RAS
+architecture allows for error records to be accessible via. system or
+memory-mapped registers.
+
+The platform should enumerate the error records providing for each of them:
+
+- A handler to probe error records for errors;
+- When the probing identifies an error, a handler to handle it;
+- For memory-mapped error record, its base address and size in KB; for a system
+ register-accessed record, the start index of the record and number of
+ continuous records from that index;
+- Any node-specific auxiliary data.
+
+With this information supplied, when the run time firmware receives one of the
+notification mechanisms, the RAS framework can iterate through and probe error
+records for error, and invoke the appropriate handler to handle it.
+
+The RAS framework provides the macros to populate error record information. The
+macros are versioned, and the latest version as of this writing is 1. These
+macros create a structure of type ``struct err_record_info`` from its arguments,
+which are later passed to probe and error handlers.
+
+For memory-mapped error records:
+
+.. code:: c
+
+ ERR_RECORD_MEMMAP_V1(base_addr, size_num_k, probe, handler, aux)
+
+And, for system register ones:
+
+.. code:: c
+
+ ERR_RECORD_SYSREG_V1(idx_start, num_idx, probe, handler, aux)
+
+The probe handler must have the following prototype:
+
+.. code:: c
+
+ typedef int (*err_record_probe_t)(const struct err_record_info *info,
+ int *probe_data);
+
+The probe handler must return a non-zero value if an error was detected, or 0
+otherwise. The ``probe_data`` output parameter can be used to pass any useful
+information resulting from probe to the error handler (see `below`__). For
+example, it could return the index of the record.
+
+.. __: `Standard Error Record helpers`_
+
+The error handler must have the following prototype:
+
+.. code:: c
+
+ typedef int (*err_record_handler_t)(const struct err_record_info *info,
+ int probe_data, const struct err_handler_data *const data);
+
+The ``data`` constant parameter describes the various properties of the error,
+viz. the reason for the error, exception syndrome, and also ``flags``,
+``cookie``, and ``handle`` parameters from the `top-level exception handler`__.
+
+.. __: interrupt-framework-design.rst#el3-interrupts
+
+The platform is expected populate an array using the macros above, and register
+the it with the RAS framework using the macro ``REGISTER_ERR_RECORD_INFO()``,
+passing it the name of the array describing the records. Note that the macro
+must be used in the same file where the array is defined.
+
+Standard Error Record helpers
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The |TF-A| RAS framework provides probe handlers for Standard Error Records, for
+both memory-mapped and System Register accesses:
+
+.. code:: c
+
+ int ras_err_ser_probe_memmap(const struct err_record_info *info,
+ int *probe_data);
+
+ int ras_err_ser_probe_sysreg(const struct err_record_info *info,
+ int *probe_data);
+
+When the platform enumerates error records, for those records in the Standard
+Error Record format, these helpers maybe used instead of rolling out their own.
+Both helpers above:
+
+- Return non-zero value when an error is detected in a Standard Error Record;
+- Set ``probe_data`` to the index of the error record upon detecting an error.
+
+Registering RAS interrupts
+--------------------------
+
+RAS nodes can signal errors to the PE by raising Fault Handling and/or Error
+Recovery interrupts. For the firmware-first handling paradigm for interrupts to
+work, the platform must setup and register with |EHF|. See `Interaction with
+Exception Handling Framework`_.
+
+For each RAS interrupt, the platform has to provide structure of type ``struct
+ras_interrupt``:
+
+- Interrupt number;
+- The associated error record information (pointer to the corresponding
+ ``struct err_record_info``);
+- Optionally, a cookie.
+
+The platform is expected to define an array of ``struct ras_interrupt``, and
+register it with the RAS framework using the macro
+``REGISTER_RAS_INTERRUPTS()``, passing it the name of the array. Note that the
+macro must be used in the same file where the array is defined.
+
+The array of ``struct ras_interrupt`` must be sorted in the increasing order of
+interrupt number. This allows for fast look of handlers in order to service RAS
+interrupts.
+
+Double-fault handling
+---------------------
+
+A Double Fault condition arises when an error is signalled to the PE while
+handling of a previously signalled error is still underway. When a Double Fault
+condition arises, the Arm RAS extensions only require for handler to perform
+orderly shutdown of the system, as recovery may be impossible.
+
+The RAS extensions part of Armv8.4 introduced new architectural features to deal
+with Double Fault conditions, specifically, the introduction of ``NMEA`` and
+``EASE`` bits to ``SCR_EL3`` register. These were introduced to assist EL3
+software which runs part of its entry/exit routines with exceptions momentarily
+masked—meaning, in such systems, External Aborts/SErrors are not immediately
+handled when they occur, but only after the exceptions are unmasked again.
+
+|TF-A|, for legacy reasons, executes entire EL3 with all exceptions unmasked.
+This means that all exceptions routed to EL3 are handled immediately. |TF-A|
+thus is able to detect a Double Fault conditions in software, without needing
+the intended advantages of Armv8.4 Double Fault architecture extensions.
+
+Double faults are fatal, and terminate at the platform double fault handler, and
+doesn't return.
+
+Engaging the RAS framework
+--------------------------
+
+Enabling RAS support is a platform choice conjunctional of three distinct but
+related build options:
+
+- ``RAS_EXTENSION=1`` includes the RAS framework in the run time firmware;
+
+- ``EL3_EXCEPTION_HANDLING=1`` enables handling of exceptions at EL3. See
+ `Interaction with Exception Handling Framework`_;
+
+- ``HANDLE_EA_EL3_FIRST=1`` enables routing of External Aborts and SErrors to
+ EL3.
+
+The RAS support in |TF-A| introduces a default implementation of
+``plat_ea_handler``, the External Abort handler in EL3. When ``RAS_EXTENSION``
+is set to ``1``, it'll first call ``ras_ea_handler()`` function, which is the
+top-level RAS exception handler. ``ras_ea_handler`` is responsible for iterating
+to through platform-supplied error records, probe them, and when an error is
+identified, look up and invoke the corresponding error handler.
+
+Note that, if the platform chooses to override the ``plat_ea_handler`` function
+and intend to use the RAS framework, it must explicitly call
+``ras_ea_handler()`` from within.
+
+Similarly, for RAS interrupts, the framework defines
+``ras_interrupt_handler()``. The RAS framework arranges for it to be invoked
+when a RAS interrupt taken at EL3. The function bisects the platform-supplied
+sorted array of interrupts to look up the error record information associated
+with the interrupt number. That error handler for that record is then invoked to
+handle the error.
+
+Interaction with Exception Handling Framework
+---------------------------------------------
+
+As mentioned in earlier sections, RAS framework interacts with the |EHF| to
+arbitrate handling of RAS exceptions with others that are routed to EL3. This
+means that the platform must partition a `priority level`__ for handling RAS
+exceptions. The platform must then define the macro ``PLAT_RAS_PRI`` to the
+priority level used for RAS exceptions. Platforms would typically want to
+allocate the highest secure priority for RAS handling.
+
+.. __: exception-handling.rst#partitioning-priority-levels
+
+Handling of both `interrrupt`__ and `non-interrupt`__ exceptions follow the
+sequences outlined in the |EHF| documentation. I.e., for interrupts, the
+priority management is implicit; but for non-interrupt exceptions, they're
+explicit using `EHF APIs`__.
+
+.. __: exception-handling.rst#interrupt-flow
+.. __: exception-handling.rst#non-interrupt-flow
+.. __: exception-handling.rst#activating-and-deactivating-priorities
+
+----
+
+*Copyright (c) 2018, Arm Limited and Contributors. All rights reserved.*
