diff options
| author | Peter Maydell <peter.maydell@linaro.org> | 2014-03-28 15:29:48 +0000 |
|---|---|---|
| committer | Richard Henderson <rth@twiddle.net> | 2014-05-12 10:03:04 -0700 |
| commit | 5c53bb812152c3d7919cadfd47c210b181bf89ac (patch) | |
| tree | 1e6de84b05aa30c933b709bfb6097dc45b6044d0 | |
| parent | 4387345a962284c77435a9644d528d2356adecc5 (diff) | |
tcg: Avoid undefined behaviour patching code at unaligned addresses
To avoid C undefined behaviour when patching generated code,
provide wrappers tcg_patch8/16/32/64 which use the usual memcpy
trick, and use them in the i386 backend.
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
| -rw-r--r-- | tcg/i386/tcg-target.c | 12 | ||||
| -rw-r--r-- | tcg/tcg.c | 20 |
2 files changed, 26 insertions, 6 deletions
diff --git a/tcg/i386/tcg-target.c b/tcg/i386/tcg-target.c index 34ece1f80b..9a585ab5ec 100644 --- a/tcg/i386/tcg-target.c +++ b/tcg/i386/tcg-target.c @@ -151,14 +151,14 @@ static void patch_reloc(uint8_t *code_ptr, int type, if (value != (int32_t)value) { tcg_abort(); } - *(uint32_t *)code_ptr = value; + tcg_patch32(code_ptr, value); break; case R_386_PC8: value -= (uintptr_t)code_ptr; if (value != (int8_t)value) { tcg_abort(); } - *(uint8_t *)code_ptr = value; + tcg_patch8(code_ptr, value); break; default: tcg_abort(); @@ -1276,9 +1276,9 @@ static void tcg_out_qemu_ld_slow_path(TCGContext *s, TCGLabelQemuLdst *l) uint8_t **label_ptr = &l->label_ptr[0]; /* resolve label address */ - *(uint32_t *)label_ptr[0] = (uint32_t)(s->code_ptr - label_ptr[0] - 4); + tcg_patch32(label_ptr[0], s->code_ptr - label_ptr[0] - 4); if (TARGET_LONG_BITS > TCG_TARGET_REG_BITS) { - *(uint32_t *)label_ptr[1] = (uint32_t)(s->code_ptr - label_ptr[1] - 4); + tcg_patch32(label_ptr[1], s->code_ptr - label_ptr[1] - 4); } if (TCG_TARGET_REG_BITS == 32) { @@ -1360,9 +1360,9 @@ static void tcg_out_qemu_st_slow_path(TCGContext *s, TCGLabelQemuLdst *l) TCGReg retaddr; /* resolve label address */ - *(uint32_t *)label_ptr[0] = (uint32_t)(s->code_ptr - label_ptr[0] - 4); + tcg_patch32(label_ptr[0], s->code_ptr - label_ptr[0] - 4); if (TARGET_LONG_BITS > TCG_TARGET_REG_BITS) { - *(uint32_t *)label_ptr[1] = (uint32_t)(s->code_ptr - label_ptr[1] - 4); + tcg_patch32(label_ptr[1], s->code_ptr - label_ptr[1] - 4); } if (TCG_TARGET_REG_BITS == 32) { @@ -122,6 +122,11 @@ static inline void tcg_out8(TCGContext *s, uint8_t v) *s->code_ptr++ = v; } +static inline void tcg_patch8(uint8_t *p, uint8_t v) +{ + memcpy(p, &v, sizeof(v)); +} + static inline void tcg_out16(TCGContext *s, uint16_t v) { uint8_t *p = s->code_ptr; @@ -129,6 +134,11 @@ static inline void tcg_out16(TCGContext *s, uint16_t v) s->code_ptr = p + 2; } +static inline void tcg_patch16(uint8_t *p, uint16_t v) +{ + memcpy(p, &v, sizeof(v)); +} + static inline void tcg_out32(TCGContext *s, uint32_t v) { uint8_t *p = s->code_ptr; @@ -136,6 +146,11 @@ static inline void tcg_out32(TCGContext *s, uint32_t v) s->code_ptr = p + 4; } +static inline void tcg_patch32(uint8_t *p, uint32_t v) +{ + memcpy(p, &v, sizeof(v)); +} + static inline void tcg_out64(TCGContext *s, uint64_t v) { uint8_t *p = s->code_ptr; @@ -143,6 +158,11 @@ static inline void tcg_out64(TCGContext *s, uint64_t v) s->code_ptr = p + 8; } +static inline void tcg_patch64(uint8_t *p, uint64_t v) +{ + memcpy(p, &v, sizeof(v)); +} + /* label relocation processing */ static void tcg_out_reloc(TCGContext *s, uint8_t *code_ptr, int type, |