From: Rohan McLure <rmclure@linux.ibm.com>
To: linuxppc-dev@lists.ozlabs.org
Cc: Rohan McLure <rmclure@linux.ibm.com>,
Nicholas Piggin <npiggin@gmail.com>
Subject: [PATCH 04/23] powerpc/64s: Use {ZEROIZE,SAVE,REST}_GPRS macros in sc, scv 0 handlers
Date: Fri, 16 Sep 2022 15:32:41 +1000 [thread overview]
Message-ID: <20220916053300.786330-5-rmclure@linux.ibm.com> (raw)
In-Reply-To: <20220916053300.786330-1-rmclure@linux.ibm.com>
Use the convenience macros for saving/clearing/restoring gprs in keeping
with syscall calling conventions. The plural variants of these macros
can store a range of registers for concision.
This works well when the user gpr value we are hoping to save is still
live. In the syscall interrupt handlers, user register state is
sometimes juggled between registers. Hold-off from issuing the SAVE_GPR
macro for applicable neighbouring lines to highlight the delicate
register save logic.
Signed-off-by: Rohan McLure <rmclure@linux.ibm.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
---
V1 -> V2: Update summary
V2 -> V3: Update summary regarding exclusions for the SAVE_GPR marco.
Acknowledge new name for ZEROIZE_GPR{,S} macros.
V4 -> V5: Move to beginning of series
---
arch/powerpc/kernel/interrupt_64.S | 43 ++++++----------------------
1 file changed, 9 insertions(+), 34 deletions(-)
diff --git a/arch/powerpc/kernel/interrupt_64.S b/arch/powerpc/kernel/interrupt_64.S
index 71d2d9497283..7d92a7a54727 100644
--- a/arch/powerpc/kernel/interrupt_64.S
+++ b/arch/powerpc/kernel/interrupt_64.S
@@ -71,12 +71,7 @@ _ASM_NOKPROBE_SYMBOL(system_call_vectored_\name)
mfcr r12
li r11,0
/* Can we avoid saving r3-r8 in common case? */
- std r3,GPR3(r1)
- std r4,GPR4(r1)
- std r5,GPR5(r1)
- std r6,GPR6(r1)
- std r7,GPR7(r1)
- std r8,GPR8(r1)
+ SAVE_GPRS(3, 8, r1)
/* Zero r9-r12, this should only be required when restoring all GPRs */
std r11,GPR9(r1)
std r11,GPR10(r1)
@@ -149,17 +144,10 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
/* Could zero these as per ABI, but we may consider a stricter ABI
* which preserves these if libc implementations can benefit, so
* restore them for now until further measurement is done. */
- ld r0,GPR0(r1)
- ld r4,GPR4(r1)
- ld r5,GPR5(r1)
- ld r6,GPR6(r1)
- ld r7,GPR7(r1)
- ld r8,GPR8(r1)
+ REST_GPR(0, r1)
+ REST_GPRS(4, 8, r1)
/* Zero volatile regs that may contain sensitive kernel data */
- li r9,0
- li r10,0
- li r11,0
- li r12,0
+ ZEROIZE_GPRS(9, 12)
mtspr SPRN_XER,r0
/*
@@ -182,7 +170,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
ld r5,_XER(r1)
REST_NVGPRS(r1)
- ld r0,GPR0(r1)
+ REST_GPR(0, r1)
mtcr r2
mtctr r3
mtlr r4
@@ -250,12 +238,7 @@ END_BTB_FLUSH_SECTION
mfcr r12
li r11,0
/* Can we avoid saving r3-r8 in common case? */
- std r3,GPR3(r1)
- std r4,GPR4(r1)
- std r5,GPR5(r1)
- std r6,GPR6(r1)
- std r7,GPR7(r1)
- std r8,GPR8(r1)
+ SAVE_GPRS(3, 8, r1)
/* Zero r9-r12, this should only be required when restoring all GPRs */
std r11,GPR9(r1)
std r11,GPR10(r1)
@@ -345,16 +328,8 @@ END_FTR_SECTION_IFCLR(CPU_FTR_STCX_CHECKS_ADDRESS)
cmpdi r3,0
bne .Lsyscall_restore_regs
/* Zero volatile regs that may contain sensitive kernel data */
- li r0,0
- li r4,0
- li r5,0
- li r6,0
- li r7,0
- li r8,0
- li r9,0
- li r10,0
- li r11,0
- li r12,0
+ ZEROIZE_GPR(0)
+ ZEROIZE_GPRS(4, 12)
mtctr r0
mtspr SPRN_XER,r0
.Lsyscall_restore_regs_cont:
@@ -380,7 +355,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
REST_NVGPRS(r1)
mtctr r3
mtspr SPRN_XER,r4
- ld r0,GPR0(r1)
+ REST_GPR(0, r1)
REST_GPRS(4, 12, r1)
b .Lsyscall_restore_regs_cont
.Lsyscall_rst_end:
--
2.34.1
next prev parent reply other threads:[~2022-09-16 5:40 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-16 5:32 [PATCH 00/23] powerpc: Syscall wrapper and register clearing Rohan McLure
2022-09-16 5:32 ` [PATCH 01/23] powerpc: Remove asmlinkage from syscall handler definitions Rohan McLure
2022-09-16 5:32 ` [PATCH 02/23] powerpc: Save caller r3 prior to system_call_exception Rohan McLure
2022-09-16 5:32 ` [PATCH 03/23] powerpc: Add ZEROIZE_GPRS macros for register clears Rohan McLure
2022-09-16 5:32 ` Rohan McLure [this message]
2022-09-16 5:32 ` [PATCH 05/23] powerpc/32: Clarify interrupt restores with REST_GPR macro in entry_32.S Rohan McLure
2022-09-20 0:51 ` Nicholas Piggin
2022-09-16 5:32 ` [PATCH 06/23] powerpc/64e: Clarify register saves and clears with {SAVE,ZEROIZE}_GPRS Rohan McLure
2022-09-20 0:55 ` Nicholas Piggin
2022-09-16 5:32 ` [PATCH 07/23] powerpc/64s: Fix comment on interrupt handler prologue Rohan McLure
2022-09-20 0:55 ` Nicholas Piggin
2022-09-16 5:32 ` [PATCH 08/23] powerpc: Fix fallocate and fadvise64_64 compat parameter combination Rohan McLure
2022-09-16 6:54 ` Arnd Bergmann
2022-09-20 1:01 ` Nicholas Piggin
2022-09-16 5:32 ` [PATCH 09/23] asm-generic: compat: Support BE for long long args in 32-bit ABIs Rohan McLure
2022-09-20 1:06 ` Nicholas Piggin
2022-09-20 7:09 ` Arnd Bergmann
2022-09-16 5:32 ` [PATCH 10/23] powerpc: Use generic fallocate compatibility syscall Rohan McLure
2022-09-16 6:56 ` Arnd Bergmann
2022-09-16 5:32 ` [PATCH 11/23] powerpc/32: Remove powerpc select specialisation Rohan McLure
2022-09-16 5:32 ` [PATCH 12/23] powerpc: Remove direct call to personality syscall handler Rohan McLure
2022-09-16 5:32 ` [PATCH 13/23] powerpc: Remove direct call to mmap2 syscall handlers Rohan McLure
2022-09-16 5:32 ` [PATCH 14/23] powerpc: Provide do_ppc64_personality helper Rohan McLure
2022-09-16 5:32 ` [PATCH 15/23] powerpc: Adopt SYSCALL_DEFINE for arch-specific syscall handlers Rohan McLure
2022-09-16 5:48 ` Rohan McLure
2022-09-20 1:24 ` Nicholas Piggin
2022-09-16 5:32 ` [PATCH 16/23] powerpc: Include all arch-specific syscall prototypes Rohan McLure
2022-09-20 1:27 ` Nicholas Piggin
2022-09-16 5:32 ` [PATCH 17/23] powerpc: Enable compile-time check for syscall handlers Rohan McLure
2022-09-20 1:30 ` Nicholas Piggin
2022-09-16 5:32 ` [PATCH 18/23] powerpc: Use common syscall handler type Rohan McLure
2022-09-20 1:39 ` Nicholas Piggin
2022-09-16 5:32 ` [PATCH 19/23] powerpc: Provide syscall wrapper Rohan McLure
2022-09-20 1:59 ` Nicholas Piggin
2022-09-21 3:44 ` Rohan McLure
2022-09-16 5:32 ` [PATCH 20/23] powerpc/64s: Clear/restore caller gprs in syscall interrupt/return Rohan McLure
2022-09-20 2:03 ` Nicholas Piggin
2022-09-20 4:54 ` Rohan McLure
2022-09-21 5:33 ` Rohan McLure
2022-09-20 2:07 ` Nicholas Piggin
2022-09-16 5:32 ` [PATCH 21/23] powerpc/64: Add INTERRUPT_SANITIZE_REGISTERS Kconfig Rohan McLure
2022-09-20 2:10 ` Nicholas Piggin
2022-09-16 5:32 ` [PATCH 22/23] powerpc/64s: Clear gprs on interrupt routine entry in Book3S Rohan McLure
2022-09-20 2:27 ` Nicholas Piggin
2022-09-16 5:33 ` [PATCH 23/23] powerpc/64e: Clear gprs on interrupt routine entry on Book3E Rohan McLure
2022-09-16 5:58 ` [PATCH 00/23] powerpc: Syscall wrapper and register clearing Rohan McLure
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