From 3d4d34e380f33e9daa86ff3aa4c06a56c5fa1318 Mon Sep 17 00:00:00 2001 From: Tim Rowley Date: Wed, 3 Jan 2018 11:58:50 -0600 Subject: [PATCH] swr/rast: don't use 32-bit gathers for elements < 32-bits in size Using a gather for elements less than 32-bits in size can cause pagefaults when loading the last elements in a page-aligned-sized buffer. Reviewed-by: Bruce Cherniak --- .../swr/rasterizer/jitter/fetch_jit.cpp | 61 ++++++++++++++++++- 1 file changed, 60 insertions(+), 1 deletion(-) diff --git a/src/gallium/drivers/swr/rasterizer/jitter/fetch_jit.cpp b/src/gallium/drivers/swr/rasterizer/jitter/fetch_jit.cpp index 99a936d1760..ad70cbe95d3 100644 --- a/src/gallium/drivers/swr/rasterizer/jitter/fetch_jit.cpp +++ b/src/gallium/drivers/swr/rasterizer/jitter/fetch_jit.cpp @@ -741,7 +741,66 @@ void FetchJit::CreateGatherOddFormats(SWR_FORMAT format, Value* pMask, Value* pB // only works if pixel size is <= 32bits SWR_ASSERT(info.bpp <= 32); - Value *pGather = GATHERDD(VIMMED1(0), pBase, pOffsets, pMask); + Value *pGather; + if (info.bpp == 32) + { + pGather = GATHERDD(VIMMED1(0), pBase, pOffsets, pMask); + } + else + { + // Can't use 32-bit gather for items less than 32-bits, could cause page faults. + Value *pMem = ALLOCA(mSimdInt32Ty); + STORE(VIMMED1(0u), pMem); + + pBase = BITCAST(pBase, PointerType::get(mInt8Ty, 0)); + Value* pDstMem = BITCAST(pMem, mInt32PtrTy); + + for (uint32_t lane = 0; lane < mVWidth; ++lane) + { + // Get index + Value* index = VEXTRACT(pOffsets, C(lane)); + Value* mask = VEXTRACT(pMask, C(lane)); + switch (info.bpp) + { + case 8: + { + Value* pDst = BITCAST(GEP(pDstMem, C(lane)), PointerType::get(mInt8Ty, 0)); + Value* pSrc = BITCAST(GEP(pBase, index), PointerType::get(mInt8Ty, 0)); + STORE(LOAD(SELECT(mask, pSrc, pDst)), pDst); + break; + } + + case 16: + { + Value* pDst = BITCAST(GEP(pDstMem, C(lane)), PointerType::get(mInt16Ty, 0)); + Value* pSrc = BITCAST(GEP(pBase, index), PointerType::get(mInt16Ty, 0)); + STORE(LOAD(SELECT(mask, pSrc, pDst)), pDst); + break; + } + break; + + case 24: + { + // First 16-bits of data + Value* pDst = BITCAST(GEP(pDstMem, C(lane)), PointerType::get(mInt16Ty, 0)); + Value* pSrc = BITCAST(GEP(pBase, index), PointerType::get(mInt16Ty, 0)); + STORE(LOAD(SELECT(mask, pSrc, pDst)), pDst); + + // Last 8-bits of data + pDst = BITCAST(GEP(pDst, C(1)), PointerType::get(mInt8Ty, 0)); + pSrc = BITCAST(GEP(pSrc, C(1)), PointerType::get(mInt8Ty, 0)); + STORE(LOAD(SELECT(mask, pSrc, pDst)), pDst); + break; + } + + default: + SWR_INVALID("Shouldn't have BPP = %d now", info.bpp); + break; + } + } + + pGather = LOAD(pMem); + } for (uint32_t comp = 0; comp < 4; ++comp) { -- 2.30.2