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riscv: Fix 32-bit call_on_irq_stack() frame pointer ABI

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call_on_irq_stack() uses struct member offsets to set up its link in the
frame record list. On riscv32, struct stackframe is the wrong size to
maintain stack pointer alignment, so STACKFRAME_SIZE_ON_STACK includes
padding. However, the ABI requires the frame record to be placed
immediately below the address stored in s0, so the padding must come
before the struct members.

Fix the layout by making STACKFRAME_FP and STACKFRAME_RA the negative
offsets from s0, instead of the positive offsets from sp.

Fixes: 82982fdd51 ("riscv: Deduplicate IRQ stack switching")
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Matthew Bystrin <dev.mbstr@gmail.com>
Signed-off-by: Rui Qi <qirui.001@bytedance.com>
Link: https://lore.kernel.org/all/20240530001733.1407654-2-samuel.holland@sifive.com/
Reviewed-by: Nam Cao <namcao@linutronix.de>
Link: https://patch.msgid.link/20260624113148.3723541-1-qirui.001@bytedance.com
[pjw@kernel.org: cleaned up the patch tags and added Matthew's Reviewed-by]
Signed-off-by: Paul Walmsley <pjw@kernel.org>
This commit is contained in:
Samuel Holland 2026-06-24 19:31:48 +08:00 committed by Paul Walmsley
parent 57ad674d03
commit c4c7756a81
2 changed files with 6 additions and 6 deletions
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4
arch/riscv/kernel/asm-offsets.c
View File

@ -501,8 +501,8 @@ void asm_offsets(void)
OFFSET(SBI_HART_BOOT_STACK_PTR_OFFSET, sbi_hart_boot_data, stack_ptr);
DEFINE(STACKFRAME_SIZE_ON_STACK, ALIGN(sizeof(struct stackframe), STACK_ALIGN));
OFFSET(STACKFRAME_FP, stackframe, fp);
OFFSET(STACKFRAME_RA, stackframe, ra);
DEFINE(STACKFRAME_FP, offsetof(struct stackframe, fp) - sizeof(struct stackframe));
DEFINE(STACKFRAME_RA, offsetof(struct stackframe, ra) - sizeof(struct stackframe));
#ifdef CONFIG_FUNCTION_TRACER
DEFINE(FTRACE_OPS_FUNC, offsetof(struct ftrace_ops, func));
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS

8
arch/riscv/kernel/entry.S
View File

@ -386,8 +386,8 @@ SYM_CODE_END(ret_from_fork_user_asm)
SYM_FUNC_START(call_on_irq_stack)
/* Create a frame record to save ra and s0 (fp) */
addi sp, sp, -STACKFRAME_SIZE_ON_STACK
REG_S ra, STACKFRAME_RA(sp)
REG_S s0, STACKFRAME_FP(sp)
REG_S ra, (STACKFRAME_SIZE_ON_STACK + STACKFRAME_RA)(sp)
REG_S s0, (STACKFRAME_SIZE_ON_STACK + STACKFRAME_FP)(sp)
addi s0, sp, STACKFRAME_SIZE_ON_STACK
/* Switch to the per-CPU shadow call stack */
@ -405,8 +405,8 @@ SYM_FUNC_START(call_on_irq_stack)
/* Switch back to the thread stack and restore ra and s0 */
addi sp, s0, -STACKFRAME_SIZE_ON_STACK
REG_L ra, STACKFRAME_RA(sp)
REG_L s0, STACKFRAME_FP(sp)
REG_L ra, (STACKFRAME_SIZE_ON_STACK + STACKFRAME_RA)(sp)
REG_L s0, (STACKFRAME_SIZE_ON_STACK + STACKFRAME_FP)(sp)
addi sp, sp, STACKFRAME_SIZE_ON_STACK
ret