From: Nicholas Piggin <npiggin@gmail•com>
To: linuxppc-dev@lists•ozlabs.org
Cc: Nicholas Piggin <npiggin@gmail•com>
Subject: [RFC PATCH 02/19] powerpc: Rearrange copy_thread child stack creation
Date: Mon, 31 Oct 2022 15:54:23 +1000 [thread overview]
Message-ID: <20221031055440.3594315-3-npiggin@gmail.com> (raw)
In-Reply-To: <20221031055440.3594315-1-npiggin@gmail.com>
This makes it a bit clearer where the stack frame is created, and will
allow easier use of some of the stack offset constants in a later
change.
Signed-off-by: Nicholas Piggin <npiggin@gmail•com>
---
arch/powerpc/kernel/process.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 67da147fe34d..acfa197fb2df 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1726,13 +1726,16 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
klp_init_thread_info(p);
+ /* Create initial stack frame. */
+ sp -= (sizeof(struct pt_regs) + STACK_FRAME_OVERHEAD);
+ ((unsigned long *)sp)[0] = 0;
+
/* Copy registers */
- sp -= sizeof(struct pt_regs);
- childregs = (struct pt_regs *) sp;
+ childregs = (struct pt_regs *)(sp + STACK_FRAME_OVERHEAD);
if (unlikely(args->fn)) {
/* kernel thread */
memset(childregs, 0, sizeof(struct pt_regs));
- childregs->gpr[1] = sp + sizeof(struct pt_regs);
+ childregs->gpr[1] = sp + (sizeof(struct pt_regs) + STACK_FRAME_OVERHEAD);
/* function */
if (args->fn)
childregs->gpr[14] = ppc_function_entry((void *)args->fn);
@@ -1767,7 +1770,6 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
f = ret_from_fork;
}
childregs->msr &= ~(MSR_FP|MSR_VEC|MSR_VSX);
- sp -= STACK_FRAME_OVERHEAD;
/*
* The way this works is that at some point in the future
@@ -1777,7 +1779,6 @@ 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.
*/
- ((unsigned long *)sp)[0] = 0;
sp -= sizeof(struct pt_regs);
kregs = (struct pt_regs *) sp;
sp -= STACK_FRAME_OVERHEAD;
--
2.37.2
next prev parent reply other threads:[~2022-10-31 5:57 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 ` Nicholas Piggin [this message]
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 ` [RFC PATCH 11/19] powerpc: add a define for the switch frame size and regs offset Nicholas Piggin
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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