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PowerPC LE setjmp/longjmp
- From: Alan Modra <amodra at gmail dot com>
- To: libc-alpha at sourceware dot org
- Date: Fri, 9 Aug 2013 14:21:21 +0930
- Subject: PowerPC LE setjmp/longjmp
Little-endian fixes for setjmp/longjmp. When writing these I noticed
the setjmp code corrupts the non volatile VMX registers when using an
unaligned buffer. Anton fixed this, and also simplified it quite a
bit.
The current code uses boilerplate for the case where we want to store
16 bytes to an unaligned address. For that we have to do a
read/modify/write of two aligned 16 byte quantities. In our case we
are storing a bunch of back to back data (consective VMX registers),
and only the start and end of the region need the read/modify/write.
2013-07-10 Anton Blanchard <anton@au1.ibm.com>
Alistair Popple <alistair@ozlabs.au.ibm.com>
Alan Modra <amodra@gmail.com>
PR 15723
* sysdeps/powerpc/jmpbuf-offsets.h: Comment fix.
* sysdeps/powerpc/powerpc32/fpu/__longjmp-common.S: Correct
_dl_hwcap access for little-endian.
* sysdeps/powerpc/powerpc32/fpu/setjmp-common.S: Likewise. Don't
destroy vmx regs when saving unaligned.
* sysdeps/powerpc/powerpc64/__longjmp-common.S: Correct CR load.
* sysdeps/powerpc/powerpc64/setjmp-common.S: Likewise CR save. Don't
destroy vmx regs when saving unaligned.
diff --git a/sysdeps/powerpc/jmpbuf-offsets.h b/sysdeps/powerpc/jmpbuf-offsets.h
index 64c658a..f2116bd 100644
--- a/sysdeps/powerpc/jmpbuf-offsets.h
+++ b/sysdeps/powerpc/jmpbuf-offsets.h
@@ -21,12 +21,10 @@
#define JB_LR 2 /* The address we will return to */
#if __WORDSIZE == 64
# define JB_GPRS 3 /* GPRs 14 through 31 are saved, 18*2 words total. */
-# define JB_CR 21 /* Condition code registers with the VRSAVE at */
- /* offset 172 (low half of the double word. */
+# define JB_CR 21 /* Shared dword with VRSAVE. CR word at offset 172. */
# define JB_FPRS 22 /* FPRs 14 through 31 are saved, 18*2 words total. */
# define JB_SIZE (64 * 8) /* As per PPC64-VMX ABI. */
-# define JB_VRSAVE 21 /* VRSAVE shares a double word with the CR at offset */
- /* 168 (high half of the double word). */
+# define JB_VRSAVE 21 /* Shared dword with CR. VRSAVE word at offset 168. */
# define JB_VRS 40 /* VRs 20 through 31 are saved, 12*4 words total. */
#else
# define JB_GPRS 3 /* GPRs 14 through 31 are saved, 18 in total. */
diff --git a/sysdeps/powerpc/powerpc32/fpu/__longjmp-common.S b/sysdeps/powerpc/powerpc32/fpu/__longjmp-common.S
index 9d34cd9..e44161d 100644
--- a/sysdeps/powerpc/powerpc32/fpu/__longjmp-common.S
+++ b/sysdeps/powerpc/powerpc32/fpu/__longjmp-common.S
@@ -43,16 +49,16 @@ ENTRY (__longjmp)
# endif
mtlr r6
cfi_same_value (lr)
- lwz r5,RTLD_GLOBAL_RO_DL_HWCAP_OFFSET+4(r5)
+ lwz r5,RTLD_GLOBAL_RO_DL_HWCAP_OFFSET+LOWORD(r5)
# else
lwz r5,_dl_hwcap@got(r5)
mtlr r6
cfi_same_value (lr)
- lwz r5,4(r5)
+ lwz r5,LOWORD(r5)
# endif
# else
- lis r5,(_dl_hwcap+4)@ha
- lwz r5,(_dl_hwcap+4)@l(r5)
+ lis r5,(_dl_hwcap+LOWORD)@ha
+ lwz r5,(_dl_hwcap+LOWORD)@l(r5)
# endif
andis. r5,r5,(PPC_FEATURE_HAS_ALTIVEC >> 16)
beq L(no_vmx)
diff --git a/sysdeps/powerpc/powerpc32/fpu/setjmp-common.S b/sysdeps/powerpc/powerpc32/fpu/setjmp-common.S
index 46ea2b0..14cb4ca 100644
--- a/sysdeps/powerpc/powerpc32/fpu/setjmp-common.S
+++ b/sysdeps/powerpc/powerpc32/fpu/setjmp-common.S
@@ -94,14 +100,14 @@ ENTRY (__sigsetjmp)
# else
lwz r5,_rtld_global_ro@got(r5)
# endif
- lwz r5,RTLD_GLOBAL_RO_DL_HWCAP_OFFSET+4(r5)
+ lwz r5,RTLD_GLOBAL_RO_DL_HWCAP_OFFSET+LOWORD(r5)
# else
lwz r5,_dl_hwcap@got(r5)
- lwz r5,4(r5)
+ lwz r5,LOWORD(r5)
# endif
# else
- lis r6,(_dl_hwcap+4)@ha
- lwz r5,(_dl_hwcap+4)@l(r6)
+ lis r6,(_dl_hwcap+LOWORD)@ha
+ lwz r5,(_dl_hwcap+LOWORD)@l(r6)
# endif
andis. r5,r5,(PPC_FEATURE_HAS_ALTIVEC >> 16)
beq L(no_vmx)
@@ -111,44 +117,43 @@ ENTRY (__sigsetjmp)
stw r0,((JB_VRSAVE)*4)(3)
addi r6,r5,16
beq+ L(aligned_save_vmx)
- lvsr v0,0,r5
- vspltisb v1,-1 /* set v1 to all 1's */
- vspltisb v2,0 /* set v2 to all 0's */
- vperm v3,v2,v1,v0 /* v3 contains shift mask with num all 1 bytes on left = misalignment */
+ lvsr v0,0,r5
+ lvsl v1,0,r5
+ addi r6,r5,-16
- /* Special case for v20 we need to preserve what is in save area below v20 before obliterating it */
- lvx v5,0,r5
- vperm v20,v20,v20,v0
- vsel v5,v5,v20,v3
- vsel v20,v20,v2,v3
- stvx v5,0,r5
+# define save_misaligned_vmx(savevr,prevvr,shiftvr,tmpvr,savegpr,addgpr) \
+ addi addgpr,addgpr,32; \
+ vperm tmpvr,prevvr,savevr,shiftvr; \
+ stvx tmpvr,0,savegpr
-#define save_2vmx_partial(savevr,prev_savevr,hivr,shiftvr,maskvr,savegpr,addgpr) \
- addi addgpr,addgpr,32; \
- vperm savevr,savevr,savevr,shiftvr; \
- vsel hivr,prev_savevr,savevr,maskvr; \
- stvx hivr,0,savegpr;
+ /*
+ * We have to be careful not to corrupt the data below v20 and
+ * above v31. To keep things simple we just rotate both ends in
+ * the opposite direction to our main permute so we can use
+ * the common macro.
+ */
- save_2vmx_partial(v21,v20,v5,v0,v3,r6,r5)
- save_2vmx_partial(v22,v21,v5,v0,v3,r5,r6)
- save_2vmx_partial(v23,v22,v5,v0,v3,r6,r5)
- save_2vmx_partial(v24,v23,v5,v0,v3,r5,r6)
- save_2vmx_partial(v25,v24,v5,v0,v3,r6,r5)
- save_2vmx_partial(v26,v25,v5,v0,v3,r5,r6)
- save_2vmx_partial(v27,v26,v5,v0,v3,r6,r5)
- save_2vmx_partial(v28,v27,v5,v0,v3,r5,r6)
- save_2vmx_partial(v29,v28,v5,v0,v3,r6,r5)
- save_2vmx_partial(v30,v29,v5,v0,v3,r5,r6)
+ /* load and rotate data below v20 */
+ lvx v2,0,r5
+ vperm v2,v2,v2,v1
+ save_misaligned_vmx(v20,v2,v0,v3,r5,r6)
+ save_misaligned_vmx(v21,v20,v0,v3,r6,r5)
+ save_misaligned_vmx(v22,v21,v0,v3,r5,r6)
+ save_misaligned_vmx(v23,v22,v0,v3,r6,r5)
+ save_misaligned_vmx(v24,v23,v0,v3,r5,r6)
+ save_misaligned_vmx(v25,v24,v0,v3,r6,r5)
+ save_misaligned_vmx(v26,v25,v0,v3,r5,r6)
+ save_misaligned_vmx(v27,v26,v0,v3,r6,r5)
+ save_misaligned_vmx(v28,v27,v0,v3,r5,r6)
+ save_misaligned_vmx(v29,v28,v0,v3,r6,r5)
+ save_misaligned_vmx(v30,v29,v0,v3,r5,r6)
+ save_misaligned_vmx(v31,v30,v0,v3,r6,r5)
+ /* load and rotate data above v31 */
+ lvx v2,0,r6
+ vperm v2,v2,v2,v1
+ save_misaligned_vmx(v2,v31,v0,v3,r5,r6)
- /* Special case for r31 we need to preserve what is in save area above v31 before obliterating it */
- addi r5,r5,32
- vperm v31,v31,v31,v0
- lvx v4,0,r5
- vsel v5,v30,v31,v3
- stvx v5,0,r6
- vsel v4,v31,v4,v3
- stvx v4,0,r5
b L(no_vmx)
L(aligned_save_vmx):
diff --git a/sysdeps/powerpc/powerpc64/__longjmp-common.S b/sysdeps/powerpc/powerpc64/__longjmp-common.S
index 70c3704..21ff50f 100644
--- a/sysdeps/powerpc/powerpc64/__longjmp-common.S
+++ b/sysdeps/powerpc/powerpc64/__longjmp-common.S
@@ -153,7 +153,7 @@ L(no_vmx):
lfd fp21,((JB_FPRS+7)*8)(r3)
ld r22,((JB_GPRS+8)*8)(r3)
lfd fp22,((JB_FPRS+8)*8)(r3)
- ld r0,(JB_CR*8)(r3)
+ lwz r0,((JB_CR*8)+4)(r3)
ld r23,((JB_GPRS+9)*8)(r3)
lfd fp23,((JB_FPRS+9)*8)(r3)
ld r24,((JB_GPRS+10)*8)(r3)
diff --git a/sysdeps/powerpc/powerpc64/setjmp-common.S b/sysdeps/powerpc/powerpc64/setjmp-common.S
index 58ec610..1c8b7cb 100644
--- a/sysdeps/powerpc/powerpc64/setjmp-common.S
+++ b/sysdeps/powerpc/powerpc64/setjmp-common.S
@@ -95,7 +95,7 @@ JUMPTARGET(GLUE(__sigsetjmp,_ent)):
mfcr r0
std r16,((JB_GPRS+2)*8)(3)
stfd fp16,((JB_FPRS+2)*8)(3)
- std r0,(JB_CR*8)(3)
+ stw r0,((JB_CR*8)+4)(3)
std r17,((JB_GPRS+3)*8)(3)
stfd fp17,((JB_FPRS+3)*8)(3)
std r18,((JB_GPRS+4)*8)(3)
@@ -142,47 +142,43 @@ JUMPTARGET(GLUE(__sigsetjmp,_ent)):
stw r0,((JB_VRSAVE)*8)(3)
addi r6,r5,16
beq+ L(aligned_save_vmx)
- lvsr v0,0,r5
- vspltisb v1,-1 /* set v1 to all 1's */
- vspltisb v2,0 /* set v2 to all 0's */
- vperm v3,v2,v1,v0 /* v3 contains shift mask with num all 1 bytes
- on left = misalignment */
+ lvsr v0,0,r5
+ lvsl v1,0,r5
+ addi r6,r5,-16
- /* Special case for v20 we need to preserve what is in save area
- below v20 before obliterating it */
- lvx v5,0,r5
- vperm v20,v20,v20,v0
- vsel v5,v5,v20,v3
- vsel v20,v20,v2,v3
- stvx v5,0,r5
+# define save_misaligned_vmx(savevr,prevvr,shiftvr,tmpvr,savegpr,addgpr) \
+ addi addgpr,addgpr,32; \
+ vperm tmpvr,prevvr,savevr,shiftvr; \
+ stvx tmpvr,0,savegpr
-# define save_2vmx_partial(savevr,prev_savevr,hivr,shiftvr,maskvr,savegpr,addgpr) \
- addi addgpr,addgpr,32; \
- vperm savevr,savevr,savevr,shiftvr; \
- vsel hivr,prev_savevr,savevr,maskvr; \
- stvx hivr,0,savegpr;
+ /*
+ * We have to be careful not to corrupt the data below v20 and
+ * above v31. To keep things simple we just rotate both ends in
+ * the opposite direction to our main permute so we can use
+ * the common macro.
+ */
- save_2vmx_partial(v21,v20,v5,v0,v3,r6,r5)
- save_2vmx_partial(v22,v21,v5,v0,v3,r5,r6)
- save_2vmx_partial(v23,v22,v5,v0,v3,r6,r5)
- save_2vmx_partial(v24,v23,v5,v0,v3,r5,r6)
- save_2vmx_partial(v25,v24,v5,v0,v3,r6,r5)
- save_2vmx_partial(v26,v25,v5,v0,v3,r5,r6)
- save_2vmx_partial(v27,v26,v5,v0,v3,r6,r5)
- save_2vmx_partial(v28,v27,v5,v0,v3,r5,r6)
- save_2vmx_partial(v29,v28,v5,v0,v3,r6,r5)
- save_2vmx_partial(v30,v29,v5,v0,v3,r5,r6)
+ /* load and rotate data below v20 */
+ lvx v2,0,r5
+ vperm v2,v2,v2,v1
+ save_misaligned_vmx(v20,v2,v0,v3,r5,r6)
+ save_misaligned_vmx(v21,v20,v0,v3,r6,r5)
+ save_misaligned_vmx(v22,v21,v0,v3,r5,r6)
+ save_misaligned_vmx(v23,v22,v0,v3,r6,r5)
+ save_misaligned_vmx(v24,v23,v0,v3,r5,r6)
+ save_misaligned_vmx(v25,v24,v0,v3,r6,r5)
+ save_misaligned_vmx(v26,v25,v0,v3,r5,r6)
+ save_misaligned_vmx(v27,v26,v0,v3,r6,r5)
+ save_misaligned_vmx(v28,v27,v0,v3,r5,r6)
+ save_misaligned_vmx(v29,v28,v0,v3,r6,r5)
+ save_misaligned_vmx(v30,v29,v0,v3,r5,r6)
+ save_misaligned_vmx(v31,v30,v0,v3,r6,r5)
+ /* load and rotate data above v31 */
+ lvx v2,0,r6
+ vperm v2,v2,v2,v1
+ save_misaligned_vmx(v2,v31,v0,v3,r5,r6)
- /* Special case for r31 we need to preserve what is in save area
- above v31 before obliterating it */
- addi r5,r5,32
- vperm v31,v31,v31,v0
- lvx v4,0,r5
- vsel v5,v30,v31,v3
- stvx v5,0,r6
- vsel v4,v31,v4,v3
- stvx v4,0,r5
b L(no_vmx)
L(aligned_save_vmx):
--
Alan Modra
Australia Development Lab, IBM