diff options
| author | Jungseok Lee <jungseoklee85@gmail.com> | 2015-12-04 11:02:25 +0000 |
|---|---|---|
| committer | Jeffrey Vander Stoep <jeffv@google.com> | 2016-09-16 21:30:59 +0000 |
| commit | b7547d55d7a578f62053c86f475eabd68282e6aa (patch) | |
| tree | 2195eab46e5f4612ee8f424c70176fac905040a6 /arch/arm64/kernel/head.S | |
| parent | 611a16d0e5fe5f9f77c62551d94770e2cc825eb5 (diff) | |
UPSTREAM: arm64: Store struct thread_info in sp_el0
There is need for figuring out how to manage struct thread_info data when
IRQ stack is introduced. struct thread_info information should be copied
to IRQ stack under the current thread_info calculation logic whenever
context switching is invoked. This is too expensive to keep supporting
the approach.
Instead, this patch pays attention to sp_el0 which is an unused scratch
register in EL1 context. sp_el0 utilization not only simplifies the
management, but also prevents text section size from being increased
largely due to static allocated IRQ stack as removing masking operation
using THREAD_SIZE in many places.
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Jungseok Lee <jungseoklee85@gmail.com>
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Bug: 30369029
Patchset: per-cpu-irq-stack
(cherry picked from commit 6cdf9c7ca687e01840d0215437620a20263012fc)
Signed-off-by: Jeff Vander Stoep <jeffv@google.com>
Change-Id: I53c9f44a0772b8649f302a65a7a6519d8eebcb91
Diffstat (limited to 'arch/arm64/kernel/head.S')
| -rw-r--r-- | arch/arm64/kernel/head.S | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S index 23cfc08fc8ba..b363f340f2c7 100644 --- a/arch/arm64/kernel/head.S +++ b/arch/arm64/kernel/head.S @@ -424,6 +424,9 @@ __mmap_switched: b 1b 2: adr_l sp, initial_sp, x4 + mov x4, sp + and x4, x4, #~(THREAD_SIZE - 1) + msr sp_el0, x4 // Save thread_info str_l x21, __fdt_pointer, x5 // Save FDT pointer str_l x24, memstart_addr, x6 // Save PHYS_OFFSET mov x29, #0 @@ -606,6 +609,8 @@ ENDPROC(secondary_startup) ENTRY(__secondary_switched) ldr x0, [x21] // get secondary_data.stack mov sp, x0 + and x0, x0, #~(THREAD_SIZE - 1) + msr sp_el0, x0 // save thread_info mov x29, #0 b secondary_start_kernel ENDPROC(__secondary_switched) |