On Sat, Oct 08, 2011 at 02:43:55AM -0400, David Miller wrote: > From: Jurij Smakov <jurij@xxxxxxxxx> > Date: Sat, 8 Oct 2011 00:22:10 +0100 > > > #define RW_FP [%fp + 0x48] > > Let's just do away with this value entirely and do this the > safest way possible, since this is the slow path: > > diff --git a/sysdeps/sparc/sparc32/__longjmp.S b/sysdeps/sparc/sparc32/__longjmp.S > index a5453b4..70e8e29 100644 > --- a/sysdeps/sparc/sparc32/__longjmp.S > +++ b/sysdeps/sparc/sparc32/__longjmp.S > @@ -22,7 +22,6 @@ > #include <jmpbuf-offsets.h> > #define ENV(base,reg) [%base + (reg * 4)] > #define ST_FLUSH_WINDOWS 3 > -#define RW_FP [%fp + 0x48] > > ENTRY(__longjmp) > /* Store our arguments in global registers so we can still > @@ -55,6 +54,7 @@ LOC(loop): > ld ENV(g1,JB_SP), %o0 /* Delay slot: extract target SP. */ > > LOC(thread): > + save %sp, -96, %sp > /* > * Do a "flush register windows trap". The trap handler in the > * kernel writes all the register windows to their stack slots, and > @@ -67,15 +67,13 @@ LOC(thread): > #ifdef PTR_DEMANGLE > ld ENV(g1,JB_PC), %g5 /* Set return PC. */ > ld ENV(g1,JB_SP), %g1 /* Set saved SP on restore below. */ > - PTR_DEMANGLE2 (%o7, %g5, %g4) > + PTR_DEMANGLE2 (%i7, %g5, %g4) > PTR_DEMANGLE2 (%fp, %g1, %g4) > #else > - ld ENV(g1,JB_PC), %o7 /* Set return PC. */ > + ld ENV(g1,JB_PC), %i7 /* Set return PC. */ > ld ENV(g1,JB_SP), %fp /* Set saved SP on restore below. */ > #endif > - sub %fp, 64, %sp /* Allocate a register frame. */ > - st %g3, RW_FP /* Set saved FP on restore below. */ > - retl > + jmp %i7 + 8 > restore %g2, 0, %o0 /* Restore values from above register frame. */ I don't really see anything in the code which would ensure that after we execute this restore, fp is going to be set to target fp value (available as ENV(g1,JB_FP) or g3. It might be the responsibility of the unwinding part, but then it would not explain why such code was explicitly present in the old version. Best regards, -- Jurij Smakov jurij@xxxxxxxxx Key: http://www.wooyd.org/pgpkey/ KeyID: C99E03CC -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
