Re: [PATCH 1/3] powerpc/vdso: augment VDSO32 functions to support 64 bits build

Le 21/12/2021 à 20:36, Segher Boessenkool a écrit :

On Tue, Dec 21, 2021 at 05:49:33PM +0000, Christophe Leroy wrote:

quoted

diff --git a/arch/powerpc/kernel/vdso32/datapage.S b/arch/powerpc/kernel/vdso32/datapage.S
index 65244416ab94..db8e167f0166 100644
--- a/arch/powerpc/kernel/vdso32/datapage.S
+++ b/arch/powerpc/kernel/vdso32/datapage.S

@@ -30,11 +30,15 @@ V_FUNCTION_BEGIN(__kernel_get_syscall_map)
  	mr.	r4,r3
  	get_datapage	r3
  	mtlr	r12
+#ifdef __powerpc64__
+	addi	r3,r3,CFG_SYSCALL_MAP64
+#else
  	addi	r3,r3,CFG_SYSCALL_MAP32
+#endif
+	crclr	cr0*4+so
  	beqlr
  	li	r0,NR_syscalls
  	stw	r0,0(r4)
-	crclr	cr0*4+so
  	blr

This now clears cr0.3 if r3 is zero on entry.  Is that on purpose?

All crclr where added by commit 5d66da3d71e6 ("[PATCH] powerpc: Make the 
vDSO functions set error code (#2)")

It looks like it was properly added to ppc64's version of 
__kernel_get_syscall_map() but for ppc32 CR.SO was left undefined in 
case of early exit of __kernel_get_syscall_map()

So yes, I think the change is on purpose.

Rest looks good.

Reviewed-by: Segher Boessenkool <redacted>

Thanks
Christophe