From 3aaf33bebda8d4ffcc0fc8ef39e6c1ac68823b11 Mon Sep 17 00:00:00 2001 From: Russell King Date: Mon, 27 Nov 2017 11:22:42 +0000 Subject: ARM: avoid faulting on qemu When qemu starts a kernel in a bare environment, the default SCR has the AW and FW bits clear, which means that the kernel can't modify the PSR A or PSR F bits, and means that FIQs and imprecise aborts are always masked. When running uboot under qemu, the AW and FW SCR bits are set, and the kernel functions normally - and this is how real hardware behaves. Fix this for qemu by ignoring the FIQ bit. Fixes: 8bafae202c82 ("ARM: BUG if jumping to usermode address in kernel mode") Signed-off-by: Russell King --- arch/arm/kernel/entry-header.S | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/arm/kernel/entry-header.S b/arch/arm/kernel/entry-header.S index 75f7a4e8541a..e056c9a9aa9d 100644 --- a/arch/arm/kernel/entry-header.S +++ b/arch/arm/kernel/entry-header.S @@ -299,7 +299,7 @@ mov r2, sp ldr r1, [r2, #\offset + S_PSR] @ get calling cpsr ldr lr, [r2, #\offset + S_PC]! @ get pc - tst r1, #0xcf + tst r1, #PSR_I_BIT | 0x0f bne 1f msr spsr_cxsf, r1 @ save in spsr_svc #if defined(CONFIG_CPU_V6) || defined(CONFIG_CPU_32v6K) @@ -331,7 +331,7 @@ ldr r1, [sp, #\offset + S_PSR] @ get calling cpsr ldr lr, [sp, #\offset + S_PC] @ get pc add sp, sp, #\offset + S_SP - tst r1, #0xcf + tst r1, #PSR_I_BIT | 0x0f bne 1f msr spsr_cxsf, r1 @ save in spsr_svc -- cgit v1.2.3