| Message ID | 20170903120757.14968-7-ard.biesheuvel@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Sun, 3 Sep 2017, Ard Biesheuvel wrote: > Replace the open coded PC relative offset calculations with adr_l > and ldr_l invocations. This ensures these quantities are invariant > under runtime relocation. > > Cc: Russell King <linux@armlinux.org.uk> > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Acked-by: Nicolas Pitre <nico@linaro.org> > --- > arch/arm/kernel/head.S | 19 ++++--------------- > 1 file changed, 4 insertions(+), 15 deletions(-) > > diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S > index 0a98aec0e39d..6e9df3663a57 100644 > --- a/arch/arm/kernel/head.S > +++ b/arch/arm/kernel/head.S > @@ -386,10 +386,8 @@ ENTRY(secondary_startup) > /* > * Use the page tables supplied from __cpu_up. > */ > - adr r4, __secondary_data > - ldmia r4, {r5, r7, r12} @ address to jump to after > - sub lr, r4, r5 @ mmu has been enabled > - add r3, r7, lr > + adr_l r3, secondary_data > + mov_l r12, __secondary_switched > ldrd r4, [r3, #0] @ get secondary_data.pgdir > ARM_BE8(eor r4, r4, r5) @ Swap r5 and r4 in BE: > ARM_BE8(eor r5, r4, r5) @ it can be done in 3 steps > @@ -404,22 +402,13 @@ ARM_BE8(eor r4, r4, r5) @ without using a temp reg. > ENDPROC(secondary_startup) > ENDPROC(secondary_startup_arm) > > - /* > - * r6 = &secondary_data > - */ > ENTRY(__secondary_switched) > - ldr sp, [r7, #12] @ get secondary_data.stack > + ldr_l r7, secondary_data + 12 @ get secondary_data.stack > + mov sp, r7 > mov fp, #0 > b secondary_start_kernel > ENDPROC(__secondary_switched) > > - .align > - > - .type __secondary_data, %object > -__secondary_data: > - .long . > - .long secondary_data > - .long __secondary_switched > #endif /* defined(CONFIG_SMP) */ > > > -- > 2.11.0 > >
diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S index 0a98aec0e39d..6e9df3663a57 100644 --- a/arch/arm/kernel/head.S +++ b/arch/arm/kernel/head.S @@ -386,10 +386,8 @@ ENTRY(secondary_startup) /* * Use the page tables supplied from __cpu_up. */ - adr r4, __secondary_data - ldmia r4, {r5, r7, r12} @ address to jump to after - sub lr, r4, r5 @ mmu has been enabled - add r3, r7, lr + adr_l r3, secondary_data + mov_l r12, __secondary_switched ldrd r4, [r3, #0] @ get secondary_data.pgdir ARM_BE8(eor r4, r4, r5) @ Swap r5 and r4 in BE: ARM_BE8(eor r5, r4, r5) @ it can be done in 3 steps @@ -404,22 +402,13 @@ ARM_BE8(eor r4, r4, r5) @ without using a temp reg. ENDPROC(secondary_startup) ENDPROC(secondary_startup_arm) - /* - * r6 = &secondary_data - */ ENTRY(__secondary_switched) - ldr sp, [r7, #12] @ get secondary_data.stack + ldr_l r7, secondary_data + 12 @ get secondary_data.stack + mov sp, r7 mov fp, #0 b secondary_start_kernel ENDPROC(__secondary_switched) - .align - - .type __secondary_data, %object -__secondary_data: - .long . - .long secondary_data - .long __secondary_switched #endif /* defined(CONFIG_SMP) */
Replace the open coded PC relative offset calculations with adr_l and ldr_l invocations. This ensures these quantities are invariant under runtime relocation. Cc: Russell King <linux@armlinux.org.uk> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> --- arch/arm/kernel/head.S | 19 ++++--------------- 1 file changed, 4 insertions(+), 15 deletions(-)