From: Rohan McLure <rmclure@linux.ibm.com>
To: linuxppc-dev@lists.ozlabs.org
Cc: Rohan McLure <rmclure@linux.ibm.com>
Subject: [PATCH v4 12/20] Revert "powerpc/syscall: Save r3 in regs->orig_r3"
Date: Wed, 24 Aug 2022 12:05:40 +1000 [thread overview]
Message-ID: <20220824020548.62625-13-rmclure@linux.ibm.com> (raw)
In-Reply-To: <20220824020548.62625-1-rmclure@linux.ibm.com>
This reverts commit 8875f47b7681aa4e4484a9b612577b044725f839.
Save caller's original r3 state to the kernel stackframe before entering
system_call_exception. This allows for user registers to be cleared by
the time system_call_exception is entered, reducing the influence of
user registers on speculation within the kernel.
Prior to this commit, orig_r3 was saved at the beginning of
system_call_exception. Instead, save orig_r3 while the user value is
still live in r3.
Also replicate this early save in 32-bit. A similar save was removed in
commit 6f76a01173cc ("powerpc/syscall: implement system call entry/exit logic in C for PPC32")
when 32-bit adopted system_call_exception. Revert its removal of orig_r3
saves.
Signed-off-by: Rohan McLure <rmclure@linux.ibm.com>
---
V2 -> V3: New commit.
---
arch/powerpc/kernel/entry_32.S | 1 +
arch/powerpc/kernel/interrupt_64.S | 2 ++
arch/powerpc/kernel/syscall.c | 1 -
3 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
index 1d599df6f169..44dfce9a60c5 100644
--- a/arch/powerpc/kernel/entry_32.S
+++ b/arch/powerpc/kernel/entry_32.S
@@ -101,6 +101,7 @@ __kuep_unlock:
.globl transfer_to_syscall
transfer_to_syscall:
+ stw r3, ORIG_GPR3(r1)
stw r11, GPR1(r1)
stw r11, 0(r1)
mflr r12
diff --git a/arch/powerpc/kernel/interrupt_64.S b/arch/powerpc/kernel/interrupt_64.S
index ce25b28cf418..71d2d9497283 100644
--- a/arch/powerpc/kernel/interrupt_64.S
+++ b/arch/powerpc/kernel/interrupt_64.S
@@ -91,6 +91,7 @@ _ASM_NOKPROBE_SYMBOL(system_call_vectored_\name)
li r11,\trapnr
std r11,_TRAP(r1)
std r12,_CCR(r1)
+ std r3,ORIG_GPR3(r1)
addi r10,r1,STACK_FRAME_OVERHEAD
ld r11,exception_marker@toc(r2)
std r11,-16(r10) /* "regshere" marker */
@@ -275,6 +276,7 @@ END_BTB_FLUSH_SECTION
std r10,_LINK(r1)
std r11,_TRAP(r1)
std r12,_CCR(r1)
+ std r3,ORIG_GPR3(r1)
addi r10,r1,STACK_FRAME_OVERHEAD
ld r11,exception_marker@toc(r2)
std r11,-16(r10) /* "regshere" marker */
diff --git a/arch/powerpc/kernel/syscall.c b/arch/powerpc/kernel/syscall.c
index 81ace9e8b72b..64102a64fd84 100644
--- a/arch/powerpc/kernel/syscall.c
+++ b/arch/powerpc/kernel/syscall.c
@@ -25,7 +25,6 @@ notrace long system_call_exception(long r3, long r4, long r5,
kuap_lock();
add_random_kstack_offset();
- regs->orig_gpr3 = r3;
if (IS_ENABLED(CONFIG_PPC_IRQ_SOFT_MASK_DEBUG))
BUG_ON(irq_soft_mask_return() != IRQS_ALL_DISABLED);
--
2.34.1
next prev parent reply other threads:[~2022-08-24 2:15 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-24 2:05 [PATCH v4 00/20] powerpc: Syscall wrapper and register clearing Rohan McLure
2022-08-24 2:05 ` [PATCH v4 01/20] powerpc: Remove asmlinkage from syscall handler definitions Rohan McLure
2022-08-25 7:04 ` Andrew Donnellan
2022-09-12 8:20 ` Nicholas Piggin
2022-08-24 2:05 ` [PATCH v4 02/20] powerpc: Use generic fallocate compatibility syscall Rohan McLure
2022-09-12 8:38 ` Nicholas Piggin
2022-09-12 9:57 ` Arnd Bergmann
2022-09-12 11:00 ` Christophe Leroy
2022-09-12 11:07 ` Arnd Bergmann
2022-08-24 2:05 ` [PATCH v4 03/20] powerpc/32: Remove powerpc select specialisation Rohan McLure
2022-09-12 9:03 ` Nicholas Piggin
2022-09-15 4:36 ` Rohan McLure
2022-08-24 2:05 ` [PATCH v4 04/20] powerpc: Provide do_ppc64_personality helper Rohan McLure
2022-09-12 9:26 ` Nicholas Piggin
2022-08-24 2:05 ` [PATCH v4 05/20] powerpc: Remove direct call to personality syscall handler Rohan McLure
2022-09-12 9:42 ` Nicholas Piggin
2022-08-24 2:05 ` [PATCH v4 06/20] powerpc: Remove direct call to mmap2 syscall handlers Rohan McLure
2022-09-12 9:47 ` Nicholas Piggin
2022-09-15 5:06 ` Rohan McLure
2022-08-24 2:05 ` [PATCH v4 07/20] powerpc: Adopt SYSCALL_DEFINE for arch-specific " Rohan McLure
2022-09-12 10:04 ` Nicholas Piggin
2022-08-24 2:05 ` [PATCH v4 08/20] powerpc: Include all arch-specific syscall prototypes Rohan McLure
2022-09-12 10:33 ` Nicholas Piggin
2022-09-13 7:09 ` Rohan McLure
2022-08-24 2:05 ` [PATCH v4 09/20] powerpc: Enable compile-time check for syscall handlers Rohan McLure
2022-09-12 10:42 ` Nicholas Piggin
2022-09-13 2:29 ` Michael Ellerman
2022-08-24 2:05 ` [PATCH v4 10/20] powerpc: Use common syscall handler type Rohan McLure
2022-09-12 10:56 ` Nicholas Piggin
2022-09-15 5:45 ` Rohan McLure
2022-09-16 1:02 ` Nicholas Piggin
2022-08-24 2:05 ` [PATCH v4 11/20] powerpc: Add ZEROIZE_GPRS macros for register clears Rohan McLure
2022-09-12 11:09 ` Nicholas Piggin
2022-09-15 5:47 ` Rohan McLure
2022-08-24 2:05 ` Rohan McLure [this message]
2022-09-12 11:14 ` [PATCH v4 12/20] Revert "powerpc/syscall: Save r3 in regs->orig_r3" Nicholas Piggin
2022-08-24 2:05 ` [PATCH v4 13/20] powerpc: Provide syscall wrapper Rohan McLure
2022-09-12 11:26 ` Nicholas Piggin
2022-08-24 2:05 ` [PATCH v4 14/20] powerpc/64s: Clear/restore caller gprs in syscall interrupt/return Rohan McLure
2022-09-12 11:47 ` Nicholas Piggin
2022-08-24 2:05 ` [PATCH v4 15/20] powerpc/64s: Use {ZEROIZE,SAVE,REST}_GPRS macros in sc, scv 0 handlers Rohan McLure
2022-09-12 11:49 ` Nicholas Piggin
2022-08-24 2:05 ` [PATCH v4 16/20] powerpc/32: Clarify interrupt restores with REST_GPR macro in entry_32.S Rohan McLure
2022-08-24 2:05 ` [PATCH v4 17/20] powerpc/64e: Clarify register saves and clears with {SAVE,ZEROIZE}_GPRS Rohan McLure
2022-09-12 12:17 ` Nicholas Piggin
2022-08-24 2:05 ` [PATCH v4 18/20] powerpc/64s: Fix comment on interrupt handler prologue Rohan McLure
2022-09-12 11:51 ` Nicholas Piggin
2022-08-24 2:05 ` [PATCH v4 19/20] powerpc/64s: Clear gprs on interrupt routine entry in Book3S Rohan McLure
2022-09-12 12:15 ` Nicholas Piggin
2022-09-15 6:55 ` Rohan McLure
2022-09-16 0:43 ` Nicholas Piggin
2022-08-24 2:05 ` [PATCH v4 20/20] powerpc/64e: Clear gprs on interrupt routine entry Rohan McLure
2022-09-12 0:55 ` [PATCH v4 00/20] powerpc: Syscall wrapper and register clearing Rohan McLure
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