From: Nicholas Piggin <npiggin@gmail•com>
To: linuxppc-dev@lists•ozlabs.org
Cc: Nicholas Piggin <npiggin@gmail•com>
Subject: [RFC PATCH 11/19] powerpc: add a define for the switch frame size and regs offset
Date: Mon, 31 Oct 2022 15:54:32 +1000 [thread overview]
Message-ID: <20221031055440.3594315-12-npiggin@gmail.com> (raw)
In-Reply-To: <20221031055440.3594315-1-npiggin@gmail.com>
This is open-coded in process.c, ppc32 uses a different define with the
same value, and the C definition is name differently which makes it an
extra indirection to grep for.
Signed-off-by: Nicholas Piggin <npiggin@gmail•com>
---
arch/powerpc/include/asm/ptrace.h | 6 ++++--
arch/powerpc/kernel/asm-offsets.c | 2 +-
arch/powerpc/kernel/entry_32.S | 6 +++---
arch/powerpc/kernel/process.c | 12 ++++++++----
4 files changed, 16 insertions(+), 10 deletions(-)
diff --git a/arch/powerpc/include/asm/ptrace.h b/arch/powerpc/include/asm/ptrace.h
index 705ce26ae887..412ef0749775 100644
--- a/arch/powerpc/include/asm/ptrace.h
+++ b/arch/powerpc/include/asm/ptrace.h
@@ -97,8 +97,6 @@ struct pt_regs
#endif
-#define STACK_FRAME_WITH_PT_REGS (STACK_FRAME_OVERHEAD + sizeof(struct pt_regs))
-
// Always displays as "REGS" in memory dumps
#ifdef CONFIG_CPU_BIG_ENDIAN
#define STACK_FRAME_REGS_MARKER ASM_CONST(0x52454753)
@@ -125,6 +123,8 @@ struct pt_regs
#define STACK_USER_INT_FRAME_SIZE (sizeof(struct pt_regs) + STACK_FRAME_OVERHEAD)
#define STACK_INT_FRAME_REGS STACK_FRAME_OVERHEAD
#define STACK_INT_FRAME_MARKER (STACK_FRAME_OVERHEAD - 16)
+#define STACK_SWITCH_FRAME_SIZE (sizeof(struct pt_regs) + STACK_FRAME_OVERHEAD)
+#define STACK_SWITCH_FRAME_REGS STACK_FRAME_OVERHEAD
#ifdef CONFIG_PPC64_ELF_ABI_V2
#define STACK_FRAME_MIN_SIZE 32
@@ -146,6 +146,8 @@ struct pt_regs
#define STACK_INT_FRAME_REGS STACK_FRAME_OVERHEAD
#define STACK_INT_FRAME_MARKER (STACK_FRAME_OVERHEAD - 8)
#define STACK_FRAME_MIN_SIZE STACK_FRAME_OVERHEAD
+#define STACK_SWITCH_FRAME_SIZE (sizeof(struct pt_regs) + STACK_FRAME_OVERHEAD)
+#define STACK_SWITCH_FRAME_REGS STACK_FRAME_OVERHEAD
/* Size of stack frame allocated when calling signal handler. */
#define __SIGNAL_FRAMESIZE 64
diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
index db5e66c1d031..f7dff906c24b 100644
--- a/arch/powerpc/kernel/asm-offsets.c
+++ b/arch/powerpc/kernel/asm-offsets.c
@@ -260,7 +260,7 @@ int main(void)
/* Interrupt register frame */
DEFINE(INT_FRAME_SIZE, STACK_INT_FRAME_SIZE);
- DEFINE(SWITCH_FRAME_SIZE, STACK_FRAME_WITH_PT_REGS);
+ DEFINE(SWITCH_FRAME_SIZE, STACK_SWITCH_FRAME_SIZE);
STACK_PT_REGS_OFFSET(GPR0, gpr[0]);
STACK_PT_REGS_OFFSET(GPR1, gpr[1]);
STACK_PT_REGS_OFFSET(GPR2, gpr[2]);
diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
index 2f61b7d3677c..6e99ec10be89 100644
--- a/arch/powerpc/kernel/entry_32.S
+++ b/arch/powerpc/kernel/entry_32.S
@@ -215,9 +215,9 @@ ret_from_kernel_thread:
* in arch/ppc/kernel/process.c
*/
_GLOBAL(_switch)
- stwu r1,-INT_FRAME_SIZE(r1)
+ stwu r1,-SWITCH_FRAME_SIZE(r1)
mflr r0
- stw r0,INT_FRAME_SIZE+4(r1)
+ stw r0,SWITCH_FRAME_SIZE+4(r1)
/* r3-r12 are caller saved -- Cort */
SAVE_NVGPRS(r1)
stw r0,_NIP(r1) /* Return to switch caller */
@@ -248,7 +248,7 @@ _GLOBAL(_switch)
lwz r4,_NIP(r1) /* Return to _switch caller in new task */
mtlr r4
- addi r1,r1,INT_FRAME_SIZE
+ addi r1,r1,SWITCH_FRAME_SIZE
blr
.globl fast_exception_return
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index d6daf0d073b3..a097879b0474 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1779,10 +1779,10 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
* do some house keeping and then return from the fork or clone
* system call, using the stack frame created above.
*/
- sp -= sizeof(struct pt_regs);
- kregs = (struct pt_regs *) sp;
- sp -= STACK_FRAME_OVERHEAD;
+ sp -= STACK_SWITCH_FRAME_SIZE;
+ kregs = (struct pt_regs *)(sp + STACK_SWITCH_FRAME_REGS);
p->thread.ksp = sp;
+
#ifdef CONFIG_HAVE_HW_BREAKPOINT
for (i = 0; i < nr_wp_slots(); i++)
p->thread.ptrace_bps[i] = NULL;
@@ -2232,8 +2232,12 @@ void __no_sanitize_address show_stack(struct task_struct *tsk,
/*
* See if this is an exception frame.
* We look for the "regs" marker in the current frame.
+ *
+ * STACK_SWITCH_FRAME_SIZE being the smallest frame that
+ * could hold a pt_regs, if that does not fit then it can't
+ * have regs.
*/
- if (validate_sp(sp, tsk, STACK_FRAME_WITH_PT_REGS)
+ if (validate_sp(sp, tsk, STACK_SWITCH_FRAME_SIZE)
&& stack[STACK_INT_FRAME_MARKER_LONGS] == STACK_FRAME_REGS_MARKER) {
struct pt_regs *regs = (struct pt_regs *)
(sp + STACK_INT_FRAME_REGS);
--
2.37.2
next prev parent reply other threads:[~2022-10-31 6:05 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-31 5:54 [RFC PATCH 00/19] Remove STACK_FRAME_OVERHEAD Nicholas Piggin
2022-10-31 5:54 ` [RFC PATCH 01/19] powerpc/perf: callchain validate kernel stack pointer bounds Nicholas Piggin
2022-11-04 13:10 ` Segher Boessenkool
2022-10-31 5:54 ` [RFC PATCH 02/19] powerpc: Rearrange copy_thread child stack creation Nicholas Piggin
2022-10-31 5:54 ` [RFC PATCH 03/19] powerpc/64: Remove asm interrupt tracing call helpers Nicholas Piggin
2022-10-31 5:54 ` [RFC PATCH 04/19] powerpc/pseries: hvcall stack frame overhead Nicholas Piggin
2022-10-31 5:54 ` [RFC PATCH 05/19] powerpc/32: Use load and store multiple in GPR save/restore macros Nicholas Piggin
2022-11-03 8:26 ` Christophe Leroy
2022-11-07 12:45 ` Nicholas Piggin
2022-11-07 12:51 ` Christophe Leroy
2022-10-31 5:54 ` [RFC PATCH 06/19] powerpc: simplify ppc_save_regs Nicholas Piggin
2022-10-31 5:54 ` [RFC PATCH 07/19] powerpc: add definition for pt_regs offset within an interrupt frame Nicholas Piggin
2022-10-31 5:54 ` [RFC PATCH 08/19] powerpc: add a definition for the marker offset within the " Nicholas Piggin
2022-10-31 5:54 ` [RFC PATCH 09/19] powerpc: Rename STACK_FRAME_MARKER and derive it from frame offset Nicholas Piggin
2022-10-31 5:54 ` [RFC PATCH 10/19] powerpc: add a define for the user interrupt frame size Nicholas Piggin
2022-10-31 5:54 ` Nicholas Piggin [this message]
2022-10-31 5:54 ` [RFC PATCH 12/19] powerpc: copy_thread fill in interrupt frame marker and back chain Nicholas Piggin
2022-10-31 5:54 ` [RFC PATCH 13/19] powerpc: copy_thread add a back chain to the switch stack frame Nicholas Piggin
2022-10-31 5:54 ` [RFC PATCH 14/19] powerpc: split validate_sp into two functions Nicholas Piggin
2022-11-07 0:58 ` Russell Currey
2022-11-07 12:29 ` Nicholas Piggin
2022-10-31 5:54 ` [RFC PATCH 15/19] powerpc: allow minimum sized kernel stack frames Nicholas Piggin
2022-10-31 5:54 ` [RFC PATCH 16/19] powerpc/64: ELFv2 use minimal stack frames in int and switch frame sizes Nicholas Piggin
2022-10-31 5:54 ` [RFC PATCH 17/19] powerpc: remove STACK_FRAME_OVERHEAD Nicholas Piggin
2022-10-31 5:54 ` [RFC PATCH 18/19] powerpc: change stack marker memory operations to 32-bit Nicholas Piggin
2022-10-31 5:54 ` [RFC PATCH 19/19] powerpc/64: ELFv2 use reserved word in the stack frame for the regs marker Nicholas Piggin
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