From 5a1717efe81a9e3435c039f896f9feeb00ec3e53 Mon Sep 17 00:00:00 2001 From: Paul Burton Date: Tue, 23 Sep 2014 11:32:28 +0100 Subject: [PATCH 12/12] MIPS: fix mfc1 & mfhc1 emulation for mips64 systems Commit bbd426f542cb "MIPS: Simplify FP context access" modified the SIFROMREG & SIFROMHREG macros such that they return unsigned rather than signed 32b integers. I had believed that to be fine, but inadvertently missed the mfc1 & mfhc1 cases which write to a struct pt_regs regs element. On mips32 this is fine, but on mips64 those saved regs fields are 64b wide. Using unsigned values caused the 32b value from the FP register to be zero rather than sign extended as the architecture specifies, causing incorrect emulation of the mfc1 & mfhc1 instructions. Fix by reintroducing the casts to signed integers, and therefore the sign extension. Signed-off-by: Paul Burton Cc: stable@vger.kernel.org # v3.15+ --- arch/mips/math-emu/cp1emu.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/mips/math-emu/cp1emu.c b/arch/mips/math-emu/cp1emu.c index bf0fc6b..7a47277 100644 --- a/arch/mips/math-emu/cp1emu.c +++ b/arch/mips/math-emu/cp1emu.c @@ -650,9 +650,9 @@ static inline int cop1_64bit(struct pt_regs *xcp) #define SIFROMREG(si, x) \ do { \ if (cop1_64bit(xcp)) \ - (si) = get_fpr32(&ctx->fpr[x], 0); \ + (si) = (int)get_fpr32(&ctx->fpr[x], 0); \ else \ - (si) = get_fpr32(&ctx->fpr[(x) & ~1], (x) & 1); \ + (si) = (int)get_fpr32(&ctx->fpr[(x) & ~1], (x) & 1); \ } while (0) #define SITOREG(si, x) \ @@ -667,7 +667,7 @@ do { \ } \ } while (0) -#define SIFROMHREG(si, x) ((si) = get_fpr32(&ctx->fpr[x], 1)) +#define SIFROMHREG(si, x) ((si) = (int)get_fpr32(&ctx->fpr[x], 1)) #define SITOHREG(si, x) \ do { \ -- 2.1.0