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| author | Chris Metcalf <cmetcalf@ezchip.com> | 2014-11-12 15:00:06 -0500 |
|---|---|---|
| committer | Chris Metcalf <cmetcalf@ezchip.com> | 2014-11-13 09:39:26 -0500 |
| commit | ce433f8090da6784cdee754defcbf325fc66f274 (patch) | |
| tree | 81be5d2025ad1690228a18203875715e0647ff04 /arch/tile | |
| parent | a5c1cb63ddf400cf58c7d8aecd045049f6818279 (diff) | |
| download | talos-op-linux-ce433f8090da6784cdee754defcbf325fc66f274.tar.gz talos-op-linux-ce433f8090da6784cdee754defcbf325fc66f274.zip | |
tile: avoid undefined behavior with regs[TREG_TP] etc
Recent compilers warn about accesses to arrays past the end,
which is supported for pt_regs and sigcontext with the
intended alias past the end of regs[] to sp, tp, and lr
using TREG_SP, TREG_TP, and TREG_LR.
Make the intended usage explict by providing an anonymous
union of regs[56] on the one hand, and a short __regs[53]
on the other followed by the sp, tp, and lr fields, so the
aliasing is done explicitly and is visible to the compiler.
Reviewed-by: Jeff Epler <jepler@unpythonic.net>
Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>
Diffstat (limited to 'arch/tile')
| -rw-r--r-- | arch/tile/include/uapi/asm/ptrace.h | 16 | ||||
| -rw-r--r-- | arch/tile/include/uapi/asm/sigcontext.h | 14 |
2 files changed, 20 insertions, 10 deletions
diff --git a/arch/tile/include/uapi/asm/ptrace.h b/arch/tile/include/uapi/asm/ptrace.h index 7757e1985fb6..d03b829857e8 100644 --- a/arch/tile/include/uapi/asm/ptrace.h +++ b/arch/tile/include/uapi/asm/ptrace.h @@ -52,12 +52,16 @@ typedef uint_reg_t pt_reg_t; * system call or exception. "struct sigcontext" has the same shape. */ struct pt_regs { - /* Saved main processor registers; 56..63 are special. */ - /* tp, sp, and lr must immediately follow regs[] for aliasing. */ - pt_reg_t regs[53]; - pt_reg_t tp; /* aliases regs[TREG_TP] */ - pt_reg_t sp; /* aliases regs[TREG_SP] */ - pt_reg_t lr; /* aliases regs[TREG_LR] */ + union { + /* Saved main processor registers; 56..63 are special. */ + pt_reg_t regs[56]; + struct { + pt_reg_t __regs[53]; + pt_reg_t tp; /* aliases regs[TREG_TP] */ + pt_reg_t sp; /* aliases regs[TREG_SP] */ + pt_reg_t lr; /* aliases regs[TREG_LR] */ + }; + }; /* Saved special registers. */ pt_reg_t pc; /* stored in EX_CONTEXT_K_0 */ diff --git a/arch/tile/include/uapi/asm/sigcontext.h b/arch/tile/include/uapi/asm/sigcontext.h index 6348e59d3724..39ff5d1a232d 100644 --- a/arch/tile/include/uapi/asm/sigcontext.h +++ b/arch/tile/include/uapi/asm/sigcontext.h @@ -24,10 +24,16 @@ * but is simplified since we know the fault is from userspace. */ struct sigcontext { - __uint_reg_t gregs[53]; /* General-purpose registers. */ - __uint_reg_t tp; /* Aliases gregs[TREG_TP]. */ - __uint_reg_t sp; /* Aliases gregs[TREG_SP]. */ - __uint_reg_t lr; /* Aliases gregs[TREG_LR]. */ + __extension__ union { + /* General-purpose registers. */ + __uint_reg_t gregs[56]; + __extension__ struct { + __uint_reg_t __gregs[53]; + __uint_reg_t tp; /* Aliases gregs[TREG_TP]. */ + __uint_reg_t sp; /* Aliases gregs[TREG_SP]. */ + __uint_reg_t lr; /* Aliases gregs[TREG_LR]. */ + }; + }; __uint_reg_t pc; /* Program counter. */ __uint_reg_t ics; /* In Interrupt Critical Section? */ __uint_reg_t faultnum; /* Fault number. */ |
