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@xxxxxxxxxx> Should this have a fixes tag? > --- > 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 > > -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!
