diff options
Diffstat (limited to 'target/linux/bcm27xx/patches-5.4/950-0927-ARM-proc-v7-Force-misalignment-of-early-stmia.patch')
| -rw-r--r-- | target/linux/bcm27xx/patches-5.4/950-0927-ARM-proc-v7-Force-misalignment-of-early-stmia.patch | 60 |
1 files changed, 0 insertions, 60 deletions
diff --git a/target/linux/bcm27xx/patches-5.4/950-0927-ARM-proc-v7-Force-misalignment-of-early-stmia.patch b/target/linux/bcm27xx/patches-5.4/950-0927-ARM-proc-v7-Force-misalignment-of-early-stmia.patch deleted file mode 100644 index 158ff69bff..0000000000 --- a/target/linux/bcm27xx/patches-5.4/950-0927-ARM-proc-v7-Force-misalignment-of-early-stmia.patch +++ /dev/null @@ -1,60 +0,0 @@ -From 965cce6b1c6acc25d7cfd29ccf95c8ebbf1d7f57 Mon Sep 17 00:00:00 2001 -From: Phil Elwell <phil@raspberrypi.com> -Date: Wed, 29 Jul 2020 13:47:55 +0100 -Subject: [PATCH] ARM: proc-v7: Force misalignment of early stmia - -In an attempt to prevent the problem of CPUn not starting, explicitly -misalign the scratch space used to save registers acros the cache -invalidation. - -Notes: -At this stage in the boot process the core is running with its cache -disabled. Before enabling the cache its contents must be explicitly -invalidated, a process that requires quite a few registers that the -caller must preserve. Evidence suggests that something is writing a -block of zeroes over that space at a time when all other cores should -be idle, possibly some kind of write-combiner, and the misalignment is -designed to disrupt any write-coalescing. - -In truth, I don't understand why this patch works, and when the failure -is so random it is hard to be certain that this isn't just rolling the -dice again. One interesting test would be to change the "addeq r12, #4"s -to "addeq r12, #0"s determine see if the offset itself is significant or -just the additional code. - -See: https://github.com/Hexxeh/rpi-firmware/issues/232 - -Signed-off-by: Phil Elwell <phil@raspberrypi.com> ---- - arch/arm/mm/proc-v7.S | 6 +++++- - 1 file changed, 5 insertions(+), 1 deletion(-) - ---- a/arch/arm/mm/proc-v7.S -+++ b/arch/arm/mm/proc-v7.S -@@ -287,6 +287,8 @@ __v7_ca17mp_setup: - mov r10, #0 - 1: adr r0, __v7_setup_stack_ptr - ldr r12, [r0] -+ tst r12, #0x1f -+ addeq r12, r12, #4 - add r12, r12, r0 @ the local stack - stmia r12, {r1-r6, lr} @ v7_invalidate_l1 touches r0-r6 - bl v7_invalidate_l1 -@@ -474,6 +476,8 @@ __v7_setup: - adr r0, __v7_setup_stack_ptr - ldr r12, [r0] - add r12, r12, r0 @ the local stack -+ tst r12, #0x1f -+ addeq r12, r12, #4 - stmia r12, {r1-r6, lr} @ v7_invalidate_l1 touches r0-r6 - bl v7_invalidate_l1 - ldmia r12, {r1-r6, lr} -@@ -557,7 +561,7 @@ ENDPROC(__v7_setup) - .bss - .align 2 - __v7_setup_stack: -- .space 4 * 7 @ 7 registers -+ .space 4 * 8 @ 7 registers + 1 spare - - __INITDATA - |