Re: [PATCH v2 01/10] ARM: p2v: fix handling of LPAE translation in BE mode
From: Russell King - ARM Linux admin <linux@armlinux.org.uk>
Date: 2020-09-21 22:23:08
Also in:
linux-efi
On Mon, Sep 21, 2020 at 05:41:08PM +0200, Ard Biesheuvel wrote:
When running in BE mode on LPAE hardware with a PA-to-VA translation that exceeds 4 GB, we patch bits 39:32 of the offset into the wrong byte of the opcode. So fix that, by rotating the offset in r0 to the right by 8 bits, which will put the 8-bit immediate in bits 31:24. Note that this will also move bit #22 in its correct place when applying the rotation to the constant #0x400000. Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Should this have a fixes tag?
quoted hunk ↗ jump to hunk
--- arch/arm/kernel/head.S | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-)diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S index f8904227e7fd..98c1e68bdfcb 100644 --- a/arch/arm/kernel/head.S +++ b/arch/arm/kernel/head.S@@ -671,12 +671,8 @@ ARM_BE8(rev16 ip, ip) ldrcc r7, [r4], #4 @ use branch for delay slot bcc 1b bx lr -#else -#ifdef CONFIG_CPU_ENDIAN_BE8 - moveq r0, #0x00004000 @ set bit 22, mov to mvn instruction #else moveq r0, #0x400000 @ set bit 22, mov to mvn instruction -#endif b 2f 1: ldr ip, [r7, r3] #ifdef CONFIG_CPU_ENDIAN_BE8@@ -685,7 +681,7 @@ ARM_BE8(rev16 ip, ip) tst ip, #0x000f0000 @ check the rotation field orrne ip, ip, r6, lsl #24 @ mask in offset bits 31-24 biceq ip, ip, #0x00004000 @ clear bit 22 - orreq ip, ip, r0 @ mask in offset bits 7-0 + orreq ip, ip, r0, ror #8 @ mask in offset bits 7-0 #else bic ip, ip, #0x000000ff tst ip, #0xf00 @ check the rotation field-- 2.17.1
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