[PATCH 1/2] powerpc/signal_32: Remove !FULL_REGS() special handling in PPC64 save_general_regs()

[PATCH 1/2] powerpc/signal_32: Remove !FULL_REGS() special handling in PPC64 save_general_regs()

[Christophe Leroy]

Since commit ("1bd79336a426 powerpc: Fix various
syscall/signal/swapcontext bugs"), getting save_general_regs() called
without FULL_REGS() is very unlikely and generates a warning.

The 32-bit version of save_general_regs() doesn't take care of it
at all and copies all registers anyway since that commit.

Moreover, commit 965dd3ad3076 ("powerpc/64/syscall: Remove
non-volatile GPR save optimisation") is another reason why it would
never happen.

So the same with 64-bit, don't worry about FULL_REGS() and copy
all registers all the time.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 arch/powerpc/kernel/signal_32.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c
index 1415c16ab628..0fd59fbc6d49 100644
--- a/arch/powerpc/kernel/signal_32.c
+++ b/arch/powerpc/kernel/signal_32.c
@@ -109,8 +109,6 @@ static inline int save_general_regs(struct pt_regs *regs,
 	WARN_ON(!FULL_REGS(regs));
 
 	for (i = 0; i <= PT_RESULT; i ++) {
-		if (i == 14 && !FULL_REGS(regs))
-			i = 32;
 		if ( i == PT_SOFTE) {
 			if(__put_user((unsigned int)softe, &frame->mc_gregs[i]))
 				return -EFAULT;
-- 
2.25.0

[PATCH 2/2] powerpc/signal_32: Simplify loop in PPC64 save_general_regs()

[Christophe Leroy]

save_general_regs() which does special handling when i == PT_SOFTE.

Rewrite it to minimise the specific part, especially the __put_user()
and associated error handling is the same so make it common.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 arch/powerpc/kernel/signal_32.c | 13 ++++---------
 1 file changed, 4 insertions(+), 9 deletions(-)

diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c
index 0fd59fbc6d49..aae31fa5e411 100644
--- a/arch/powerpc/kernel/signal_32.c
+++ b/arch/powerpc/kernel/signal_32.c
@@ -103,19 +103,14 @@ static inline int save_general_regs(struct pt_regs *regs,
 {
 	elf_greg_t64 *gregs = (elf_greg_t64 *)regs;
 	int i;
-	/* Force usr to alway see softe as 1 (interrupts enabled) */
-	elf_greg_t64 softe = 0x1;
 
 	WARN_ON(!FULL_REGS(regs));
 
 	for (i = 0; i <= PT_RESULT; i ++) {
-		if ( i == PT_SOFTE) {
-			if(__put_user((unsigned int)softe, &frame->mc_gregs[i]))
-				return -EFAULT;
-			else
-				continue;
-		}
-		if (__put_user((unsigned int)gregs[i], &frame->mc_gregs[i]))
+		/* Force usr to alway see softe as 1 (interrupts enabled) */
+		int val = (i == PT_SOFTE) ? 1 : gregs[i];
+
+		if (__put_user(val, &frame->mc_gregs[i]))
 			return -EFAULT;
 	}
 	return 0;
-- 
2.25.0

Re: [PATCH 1/2] powerpc/signal_32: Remove !FULL_REGS() special handling in PPC64 save_general_regs()

[Michael Ellerman]

On Tue, 7 Jul 2020 12:33:35 +0000 (UTC), Christophe Leroy wrote:
> Since commit ("1bd79336a426 powerpc: Fix various
> syscall/signal/swapcontext bugs"), getting save_general_regs() called
> without FULL_REGS() is very unlikely and generates a warning.
> 
> The 32-bit version of save_general_regs() doesn't take care of it
> at all and copies all registers anyway since that commit.
> 
> [...]

Applied to powerpc/next.

[1/2] powerpc/signal_32: Remove !FULL_REGS() special handling in PPC64 save_general_regs()
      https://git.kernel.org/powerpc/c/667e3c413ecf20371692fd2dc37e06dc14d0b140
[2/2] powerpc/signal_32: Simplify loop in PPC64 save_general_regs()
      https://git.kernel.org/powerpc/c/020c4831e01264f8b62af6ca9e669b7c51881a56

cheers