diff options
| author |   Ard Biesheuvel <ardb@kernel.org> | 2021-02-11 09:25:34 +0100 |
|---|---|---|
| committer |   Russell King <rmk+kernel@armlinux.org.uk> | 2021-03-09 10:25:18 +0000 |
| commit | 95731b8ee63ec9419822a51cd9878fa32582fdd2 (patch) | |
| tree | 64c4734315d802c18d6f8346246fe274457c71ec /arch/arm/mm/proc-v7.S | |
| parent | ARM: 9058/1: cache-v7: refactor v7_invalidate_l1 to avoid clobbering r5/r6 (diff) | |
| download | linux-dev-95731b8ee63ec9419822a51cd9878fa32582fdd2.tar.xz linux-dev-95731b8ee63ec9419822a51cd9878fa32582fdd2.zip | |
ARM: 9059/1: cache-v7: get rid of mini-stack
Now that we have reduced the number of registers that we need to
preserve when calling v7_invalidate_l1 from the boot code, we can use
scratch registers to preserve the remaining ones, and get rid of the
mini stack entirely. This works around any issues regarding cache
behavior in relation to the uncached accesses to this memory, which is
hard to get right in the general case (i.e., both bare metal and under
virtualization)
While at it, switch v7_invalidate_l1 to using ip as a scratch register
instead of r4. This makes the function AAPCS compliant, and removes the
need to stash r4 in ip across the call.
Acked-by: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Diffstat (limited to 'arch/arm/mm/proc-v7.S')
| -rw-r--r-- | arch/arm/mm/proc-v7.S | 39 |
1 files changed, 18 insertions, 21 deletions
diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S index 28c9d32fa99a..26d726a08a34 100644 --- a/arch/arm/mm/proc-v7.S +++ b/arch/arm/mm/proc-v7.S @@ -256,6 +256,20 @@ ENDPROC(cpu_pj4b_do_resume) #endif + @ + @ Invoke the v7_invalidate_l1() function, which adheres to the AAPCS + @ rules, and so it may corrupt registers that we need to preserve. + @ + .macro do_invalidate_l1 + mov r6, r1 + mov r7, r2 + mov r10, lr + bl v7_invalidate_l1 @ corrupts {r0-r3, ip, lr} + mov r1, r6 + mov r2, r7 + mov lr, r10 + .endm + /* * __v7_setup * @@ -277,6 +291,7 @@ __v7_ca5mp_setup: __v7_ca9mp_setup: __v7_cr7mp_setup: __v7_cr8mp_setup: + do_invalidate_l1 mov r10, #(1 << 0) @ Cache/TLB ops broadcasting b 1f __v7_ca7mp_setup: @@ -284,13 +299,9 @@ __v7_ca12mp_setup: __v7_ca15mp_setup: __v7_b15mp_setup: __v7_ca17mp_setup: + do_invalidate_l1 mov r10, #0 -1: adr r0, __v7_setup_stack_ptr - ldr r12, [r0] - add r12, r12, r0 @ the local stack - stmia r12, {r1-r6, lr} @ v7_invalidate_l1 touches r0-r6 - bl v7_invalidate_l1 - ldmia r12, {r1-r6, lr} +1: #ifdef CONFIG_SMP orr r10, r10, #(1 << 6) @ Enable SMP/nAMP mode ALT_SMP(mrc p15, 0, r0, c1, c0, 1) @@ -471,12 +482,7 @@ __v7_pj4b_setup: #endif /* CONFIG_CPU_PJ4B */ __v7_setup: - adr r0, __v7_setup_stack_ptr - ldr r12, [r0] - add r12, r12, r0 @ the local stack - stmia r12, {r1-r6, lr} @ v7_invalidate_l1 touches r0-r6 - bl v7_invalidate_l1 - ldmia r12, {r1-r6, lr} + do_invalidate_l1 __v7_setup_cont: and r0, r9, #0xff000000 @ ARM? @@ -548,17 +554,8 @@ __errata_finish: orr r0, r0, r6 @ set them THUMB( orr r0, r0, #1 << 30 ) @ Thumb exceptions ret lr @ return to head.S:__ret - - .align 2 -__v7_setup_stack_ptr: - .word PHYS_RELATIVE(__v7_setup_stack, .) ENDPROC(__v7_setup) - .bss - .align 2 -__v7_setup_stack: - .space 4 * 7 @ 7 registers - __INITDATA .weak cpu_v7_bugs_init |