From: Mark Rutland <mark.rutland@arm.com>
To: linux-arm-kernel@lists.infradead.org
Cc: ardb@kernel.org, broonie@kernel.org, catalin.marinas@arm.com,
james.morse@arm.com, madvenka@linux.microsoft.com,
mark.rutland@arm.com, maz@kernel.org, suzuki.poulose@arm.com,
will@kernel.org
Subject: [PATCH 5/6] arm64: smp: unify task and sp setup
Date: Thu, 20 May 2021 12:50:30 +0100 [thread overview]
Message-ID: <20210520115031.18509-6-mark.rutland@arm.com> (raw)
In-Reply-To: <20210520115031.18509-1-mark.rutland@arm.com>
Once we enable the MMU, we have to initialize:
* SP_EL0 to point at the active task
* SP to point at the active task's stack
* SCS_SP to point at the active task's shadow stack
For all tasks (including init_task), this information can be derived
from the task's task_struct.
Let's unify __primary_switched and __secondary_switched to consistently
acquire this information from the relevant task_struct. At the same
time, let's fold this together with initializing a task's final frame.
There should be no functional change as a result of this patch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Suzuki Poulose <suzuki.poulose@arm.com>
Cc: Will Deacon <will@kernel.org>
---
arch/arm64/kernel/head.S | 33 +++++++++++++++------------------
1 file changed, 15 insertions(+), 18 deletions(-)
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index 9be95e11367d..e83b2899dce5 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -395,15 +395,24 @@ SYM_FUNC_START_LOCAL(__create_page_tables)
SYM_FUNC_END(__create_page_tables)
/*
+ * Initialize CPU registers with task-specific and cpu-specific context.
+ *
* Create a final frame record at task_pt_regs(current)->stackframe, so
* that the unwinder can identify the final frame record of any task by
* its location in the task stack. We reserve the entire pt_regs space
* for consistency with user tasks and kthreads.
*/
- .macro setup_final_frame
+ .macro init_cpu_task tsk, tmp
+ msr sp_el0, \tsk
+
+ ldr \tmp, [\tsk, #TSK_STACK]
+ add sp, \tmp, #THREAD_SIZE
sub sp, sp, #PT_REGS_SIZE
+
stp xzr, xzr, [sp, #S_STACKFRAME]
add x29, sp, #S_STACKFRAME
+
+ scs_load \tsk, \tmp
.endm
/*
@@ -412,22 +421,16 @@ SYM_FUNC_END(__create_page_tables)
* x0 = __PHYS_OFFSET
*/
SYM_FUNC_START_LOCAL(__primary_switched)
- adrp x4, init_thread_union
- add sp, x4, #THREAD_SIZE
- adr_l x5, init_task
- msr sp_el0, x5 // Save thread_info
+ adr_l x4, init_task
+ init_cpu_task x4, x5
adr_l x8, vectors // load VBAR_EL1 with virtual
msr vbar_el1, x8 // vector table address
isb
- stp xzr, x30, [sp, #-16]!
+ stp x29, x30, [sp, #-16]!
mov x29, sp
-#ifdef CONFIG_SHADOW_CALL_STACK
- adr_l scs_sp, init_shadow_call_stack // Set shadow call stack
-#endif
-
str_l x21, __fdt_pointer, x5 // Save FDT pointer
ldr_l x4, kimage_vaddr // Save the offset between
@@ -459,8 +462,7 @@ SYM_FUNC_START_LOCAL(__primary_switched)
0:
#endif
bl switch_to_vhe // Prefer VHE if possible
- add sp, sp, #16
- setup_final_frame
+ ldp x29, x30, [sp], #16
bl start_kernel
ASM_BUG()
SYM_FUNC_END(__primary_switched)
@@ -648,12 +650,7 @@ SYM_FUNC_START_LOCAL(__secondary_switched)
ldr x2, [x0, #CPU_BOOT_TASK]
cbz x2, __secondary_too_slow
- ldr x1, [x2, #TSK_STACK]
- add sp, x1, #THREAD_SIZE
-
- msr sp_el0, x2
- scs_load x2, x3
- setup_final_frame
+ init_cpu_task x2, x1
#ifdef CONFIG_ARM64_PTR_AUTH
ptrauth_keys_init_cpu x2, x3, x4, x5
--
2.11.0
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next prev parent reply other threads:[~2021-05-20 11:55 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-20 11:50 [PATCH 0/6] arm64: boot cleanups Mark Rutland
2021-05-20 11:50 ` [PATCH 1/6] arm64: Implement stack trace termination record Mark Rutland
2021-05-20 11:50 ` [PATCH 2/6] arm64: assembler: add set_this_cpu_offset Mark Rutland
2021-05-20 11:50 ` [PATCH 3/6] arm64: smp: remove pointless secondary_data maintenance Mark Rutland
2021-05-20 11:50 ` [PATCH 4/6] arm64: smp: remove stack from secondary_data Mark Rutland
2021-05-20 11:50 ` Mark Rutland [this message]
2021-05-20 11:50 ` [PATCH 6/6] arm64: smp: initialize cpu offset earlier Mark Rutland
2021-05-20 14:46 ` [PATCH 0/6] arm64: boot cleanups Ard Biesheuvel
2021-05-26 22:16 ` Will Deacon
2021-05-27 9:33 ` Mark Rutland
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