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| author |   Russell King <rmk+kernel@armlinux.org.uk> | 2017-11-27 11:22:42 +0000 |
|---|---|---|
| committer | Russell King <rmk+kernel@armlinux.org.uk> | 2017-11-27 11:22:42 +0000 |
| commit | 3aaf33bebda8d4ffcc0fc8ef39e6c1ac68823b11 (patch) | |
| tree | cea1260797f0c3af391c048a53f46db026221f87 /arch/arm/kernel/entry-header.S | |
| parent | ARM: BUG if jumping to usermode address in kernel mode (diff) | |
| download | linux-dev-3aaf33bebda8d4ffcc0fc8ef39e6c1ac68823b11.tar.xz linux-dev-3aaf33bebda8d4ffcc0fc8ef39e6c1ac68823b11.zip | |
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 <rmk+kernel@armlinux.org.uk>
Diffstat (limited to 'arch/arm/kernel/entry-header.S')
| -rw-r--r-- | arch/arm/kernel/entry-header.S | 4 |
1 files 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 |