From 298c26c5c7f4105f4e421d227009baeba5c59678 Mon Sep 17 00:00:00 2001 From: Sean Anderson Date: Fri, 27 Oct 2023 16:40:13 -0400 Subject: [PATCH] arm: Fix software interrupt handler When we take a software interrupt, we are already in supervisor mode. get_bad_stack assumes we are not in supervisor mode so it can clobber the stack pointer. This causes us to have an invalid stack once that macro finishes. Revert back to the get_bad_stack_swi macro which was previously removed. Fixes: 41623c91b09 ("arm: move exception handling out of start.S files") Signed-off-by: Sean Anderson --- arch/arm/lib/vectors.S | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/arch/arm/lib/vectors.S b/arch/arm/lib/vectors.S index 7cf7d1636f..fe8ca403ac 100644 --- a/arch/arm/lib/vectors.S +++ b/arch/arm/lib/vectors.S @@ -240,6 +240,18 @@ IRQ_STACK_START_IN: movs pc, lr @ jump to next instruction & switch modes. .endm + .macro get_bad_stack_swi + sub r13, r13, #4 @ space on current stack for scratch reg. + str r0, [r13] @ save R0's value. + ldr r0, IRQ_STACK_START_IN @ get data regions start + str lr, [r0] @ save caller lr in position 0 of saved stack + mrs lr, spsr @ get the spsr + str lr, [r0, #4] @ save spsr in position 1 of saved stack + ldr lr, [r0] @ restore lr + ldr r0, [r13] @ restore r0 + add r13, r13, #4 @ pop stack entry + .endm + .macro get_irq_stack @ setup IRQ stack ldr sp, IRQ_STACK_START .endm @@ -260,7 +272,7 @@ undefined_instruction: .align 5 software_interrupt: - get_bad_stack + get_bad_stack_swi bad_save_user_regs bl do_software_interrupt -- 2.39.5