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| author | Srinivas KANDAGATLA <srinivas.kandagatla@st.com> | 2011-06-08 08:22:39 +0200 |
|---|---|---|
| committer | Paul Mundt <lethal@linux-sh.org> | 2011-06-08 08:22:39 +0200 |
| commit | 5bdbd4fa4df6891a6644d588c9a30d30e7c0af8e (patch) | |
| tree | 5ae072f2628684d085b92aab2398dd873c20d619 /arch/sh/include | |
| parent | sh: Remove compressed kernel libgcc dependency. (diff) | |
| download | linux-5bdbd4fa4df6891a6644d588c9a30d30e7c0af8e.tar.xz linux-5bdbd4fa4df6891a6644d588c9a30d30e7c0af8e.zip | |
sh: Fix up xchg/cmpxchg corruption with gUSA RB.
gUSA special cases r15 for part of its login/out sequence, meaning that
any parameters need to be explicitly prohibited from accidentally being
assigned that particular register, and the compiler ultimately needs to
use a temporary instead.
Certain configurations have begun generating code paths that do indeed
get allocated r15, resulting in immediate corruption of the exchanged
value. This was observed in (amongst others) exit_mm() code generation
where the xchg_u32 call was immediately corrupting a structure address.
As this is a general gUSA restriction, the rest of the users likewise
need to be updated to ensure sensible constraints.
References: https://bugzilla.stlinux.com/show_bug.cgi?id=11229
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@st.com>
Reviewed-by: Stuart Menefy <stuart.menefy@st.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Diffstat (limited to 'arch/sh/include')
| -rw-r--r-- | arch/sh/include/asm/cmpxchg-grb.h | 21 |
1 files changed, 12 insertions, 9 deletions
diff --git a/arch/sh/include/asm/cmpxchg-grb.h b/arch/sh/include/asm/cmpxchg-grb.h index 4676bf57693a..f848dec9e483 100644 --- a/arch/sh/include/asm/cmpxchg-grb.h +++ b/arch/sh/include/asm/cmpxchg-grb.h @@ -15,8 +15,9 @@ static inline unsigned long xchg_u32(volatile u32 *m, unsigned long val) " mov.l %2, @%1 \n\t" /* store new value */ "1: mov r1, r15 \n\t" /* LOGOUT */ : "=&r" (retval), - "+r" (m) - : "r" (val) + "+r" (m), + "+r" (val) /* inhibit r15 overloading */ + : : "memory", "r0", "r1"); return retval; @@ -36,8 +37,9 @@ static inline unsigned long xchg_u8(volatile u8 *m, unsigned long val) " mov.b %2, @%1 \n\t" /* store new value */ "1: mov r1, r15 \n\t" /* LOGOUT */ : "=&r" (retval), - "+r" (m) - : "r" (val) + "+r" (m), + "+r" (val) /* inhibit r15 overloading */ + : : "memory" , "r0", "r1"); return retval; @@ -54,13 +56,14 @@ static inline unsigned long __cmpxchg_u32(volatile int *m, unsigned long old, " nop \n\t" " mov r15, r1 \n\t" /* r1 = saved sp */ " mov #-8, r15 \n\t" /* LOGIN */ - " mov.l @%1, %0 \n\t" /* load old value */ - " cmp/eq %0, %2 \n\t" + " mov.l @%3, %0 \n\t" /* load old value */ + " cmp/eq %0, %1 \n\t" " bf 1f \n\t" /* if not equal */ - " mov.l %3, @%1 \n\t" /* store new value */ + " mov.l %2, @%3 \n\t" /* store new value */ "1: mov r1, r15 \n\t" /* LOGOUT */ - : "=&r" (retval) - : "r" (m), "r" (old), "r" (new) + : "=&r" (retval), + "+r" (old), "+r" (new) /* old or new can be r15 */ + : "r" (m) : "memory" , "r0", "r1", "t"); return retval; |