| Message ID | 20240822101441.251184-7-mark.rutland@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Cleanup initialization | expand |
On Thu, 22 Aug 2024 11:14:37 +0100 Mark Rutland <mark.rutland@arm.com> wrote: > When the boot-wrapper is entered at Secure PL1 it will enter the kernel > via an exception return, and when entered at Hyp it will branch to the > kernel directly. This is an artifact of the way the boot-wrapper was > originally written in assembly, and it would be preferable to always > enter the kernel via an exception return so that PSTATE is always > initialized to a known-good value. > > Rework jump_kernel() to always enter the kernel via an exception return, > matching the style of the AArch64 version of jump_kernel() > > Signed-off-by: Mark Rutland <mark.rutland@arm.com> > Acked-by: Marc Zyngier <maz@kernel.org> > Cc: Akos Denke <akos.denke@arm.com> > Cc: Andre Przywara <andre.przywara@arm.com> > Cc: Luca Fancellu <luca.fancellu@arm.com> Thanks for the changes, looks good to me now! Reviewed-by: Andre Przywara <andre.przywara@arm.com> Cheers, Andre > --- > arch/aarch32/boot.S | 48 +++++++++++++++++++++++---------------------- > 1 file changed, 25 insertions(+), 23 deletions(-) > > diff --git a/arch/aarch32/boot.S b/arch/aarch32/boot.S > index f21f89a..e79aa06 100644 > --- a/arch/aarch32/boot.S > +++ b/arch/aarch32/boot.S > @@ -76,10 +76,6 @@ reset_at_hyp: > > bl setup_stack > > - mov r0, #1 > - ldr r1, =flag_no_el3 > - str r0, [r1] > - > bl cpu_init_bootwrapper > > bl cpu_init_arch > @@ -96,9 +92,10 @@ err_invalid_id: > * r1-r3, sp[0]: kernel arguments > */ > ASM_FUNC(jump_kernel) > - sub sp, #4 @ Ignore fourth argument > - push {r0 - r3} > - mov r5, sp > + mov r4, r0 > + mov r5, r1 > + mov r6, r2 > + mov r7, r3 > > ldr r0, =HSCTLR_KERNEL > mcr p15, 4, r0, c1, c0, 0 @ HSCTLR > @@ -111,23 +108,28 @@ ASM_FUNC(jump_kernel) > bl find_logical_id > bl setup_stack > > - ldr lr, [r5], #4 > - ldm r5, {r0 - r2} > - > - ldr r4, =flag_no_el3 > - ldr r4, [r4] > - cmp r4, #1 > - bxeq lr @ no EL3 > + mov r0, r5 > + mov r1, r6 > + mov r2, r7 > + ldr r3, =SPSR_KERNEL > > - ldr r4, =SPSR_KERNEL > /* Return in thumb2 mode when bit 0 of address is 1 */ > - tst lr, #1 > - orrne r4, #PSR_T > + tst r4, #1 > + orrne r3, #PSR_T > + > + mrs r5, cpsr > + and r5, #PSR_MODE_MASK > + cmp r5, #PSR_MON > + beq eret_at_mon > + cmp r5, #PSR_HYP > + beq eret_at_hyp > + b . > > - msr spsr_cxf, r4 > +eret_at_mon: > + mov lr, r4 > + msr spsr_mon, r3 > movs pc, lr > - > - .section .data > - .align 2 > -flag_no_el3: > - .long 0 > +eret_at_hyp: > + msr elr_hyp, r4 > + msr spsr_hyp, r3 > + eret
diff --git a/arch/aarch32/boot.S b/arch/aarch32/boot.S index f21f89a..e79aa06 100644 --- a/arch/aarch32/boot.S +++ b/arch/aarch32/boot.S @@ -76,10 +76,6 @@ reset_at_hyp: bl setup_stack - mov r0, #1 - ldr r1, =flag_no_el3 - str r0, [r1] - bl cpu_init_bootwrapper bl cpu_init_arch @@ -96,9 +92,10 @@ err_invalid_id: * r1-r3, sp[0]: kernel arguments */ ASM_FUNC(jump_kernel) - sub sp, #4 @ Ignore fourth argument - push {r0 - r3} - mov r5, sp + mov r4, r0 + mov r5, r1 + mov r6, r2 + mov r7, r3 ldr r0, =HSCTLR_KERNEL mcr p15, 4, r0, c1, c0, 0 @ HSCTLR @@ -111,23 +108,28 @@ ASM_FUNC(jump_kernel) bl find_logical_id bl setup_stack - ldr lr, [r5], #4 - ldm r5, {r0 - r2} - - ldr r4, =flag_no_el3 - ldr r4, [r4] - cmp r4, #1 - bxeq lr @ no EL3 + mov r0, r5 + mov r1, r6 + mov r2, r7 + ldr r3, =SPSR_KERNEL - ldr r4, =SPSR_KERNEL /* Return in thumb2 mode when bit 0 of address is 1 */ - tst lr, #1 - orrne r4, #PSR_T + tst r4, #1 + orrne r3, #PSR_T + + mrs r5, cpsr + and r5, #PSR_MODE_MASK + cmp r5, #PSR_MON + beq eret_at_mon + cmp r5, #PSR_HYP + beq eret_at_hyp + b . - msr spsr_cxf, r4 +eret_at_mon: + mov lr, r4 + msr spsr_mon, r3 movs pc, lr - - .section .data - .align 2 -flag_no_el3: - .long 0 +eret_at_hyp: + msr elr_hyp, r4 + msr spsr_hyp, r3 + eret