From: Srinivas KANDAGATLA Date: Wed, 8 Jun 2011 06:22:39 +0000 (+0900) Subject: sh: Fix up xchg/cmpxchg corruption with gUSA RB. X-Git-Tag: upstream/snapshot3+hdmi~9407^2~29 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=5bdbd4fa4df6891a6644d588c9a30d30e7c0af8e;p=platform%2Fadaptation%2Frenesas_rcar%2Frenesas_kernel.git 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 Reviewed-by: Stuart Menefy Signed-off-by: Paul Mundt --- diff --git a/arch/sh/include/asm/cmpxchg-grb.h b/arch/sh/include/asm/cmpxchg-grb.h index 4676bf5..f848dec 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;