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-rw-r--r--arch/arm64/kernel/sleep.S93
1 files changed, 33 insertions, 60 deletions
diff --git a/arch/arm64/kernel/sleep.S b/arch/arm64/kernel/sleep.S
index fd10eb663868..b7c4b682bfc8 100644
--- a/arch/arm64/kernel/sleep.S
+++ b/arch/arm64/kernel/sleep.S
@@ -49,37 +49,30 @@
orr \dst, \dst, \mask // dst|=(aff3>>rs3)
.endm
/*
- * Save CPU state for a suspend and execute the suspend finisher.
- * On success it will return 0 through cpu_resume - ie through a CPU
- * soft/hard reboot from the reset vector.
- * On failure it returns the suspend finisher return value or force
- * -EOPNOTSUPP if the finisher erroneously returns 0 (the suspend finisher
- * is not allowed to return, if it does this must be considered failure).
- * It saves callee registers, and allocates space on the kernel stack
- * to save the CPU specific registers + some other data for resume.
+ * Save CPU state in the provided sleep_stack_data area, and publish its
+ * location for cpu_resume()'s use in sleep_save_stash.
*
- * x0 = suspend finisher argument
- * x1 = suspend finisher function pointer
+ * cpu_resume() will restore this saved state, and return. Because the
+ * link-register is saved and restored, it will appear to return from this
+ * function. So that the caller can tell the suspend/resume paths apart,
+ * __cpu_suspend_enter() will always return a non-zero value, whereas the
+ * path through cpu_resume() will return 0.
+ *
+ * x0 = struct sleep_stack_data area
*/
ENTRY(__cpu_suspend_enter)
- stp x29, lr, [sp, #-96]!
- stp x19, x20, [sp,#16]
- stp x21, x22, [sp,#32]
- stp x23, x24, [sp,#48]
- stp x25, x26, [sp,#64]
- stp x27, x28, [sp,#80]
- /*
- * Stash suspend finisher and its argument in x20 and x19
- */
- mov x19, x0
- mov x20, x1
+ stp x29, lr, [x0, #SLEEP_STACK_DATA_CALLEE_REGS]
+ stp x19, x20, [x0,#SLEEP_STACK_DATA_CALLEE_REGS+16]
+ stp x21, x22, [x0,#SLEEP_STACK_DATA_CALLEE_REGS+32]
+ stp x23, x24, [x0,#SLEEP_STACK_DATA_CALLEE_REGS+48]
+ stp x25, x26, [x0,#SLEEP_STACK_DATA_CALLEE_REGS+64]
+ stp x27, x28, [x0,#SLEEP_STACK_DATA_CALLEE_REGS+80]
+
+ /* save the sp in cpu_suspend_ctx */
mov x2, sp
- sub sp, sp, #CPU_SUSPEND_SZ // allocate cpu_suspend_ctx
- mov x0, sp
- /*
- * x0 now points to struct cpu_suspend_ctx allocated on the stack
- */
- str x2, [x0, #CPU_CTX_SP]
+ str x2, [x0, #SLEEP_STACK_DATA_SYSTEM_REGS + CPU_CTX_SP]
+
+ /* find the mpidr_hash */
ldr x1, =sleep_save_sp
ldr x1, [x1, #SLEEP_SAVE_SP_VIRT]
mrs x7, mpidr_el1
@@ -93,34 +86,11 @@ ENTRY(__cpu_suspend_enter)
ldp w5, w6, [x9, #(MPIDR_HASH_SHIFTS + 8)]
compute_mpidr_hash x8, x3, x4, x5, x6, x7, x10
add x1, x1, x8, lsl #3
+
+ stp x29, lr, [sp, #-16]!
bl __cpu_suspend_save
- /*
- * Grab suspend finisher in x20 and its argument in x19
- */
- mov x0, x19
- mov x1, x20
- /*
- * We are ready for power down, fire off the suspend finisher
- * in x1, with argument in x0
- */
- blr x1
- /*
- * Never gets here, unless suspend finisher fails.
- * Successful cpu_suspend should return from cpu_resume, returning
- * through this code path is considered an error
- * If the return value is set to 0 force x0 = -EOPNOTSUPP
- * to make sure a proper error condition is propagated
- */
- cmp x0, #0
- mov x3, #-EOPNOTSUPP
- csel x0, x3, x0, eq
- add sp, sp, #CPU_SUSPEND_SZ // rewind stack pointer
- ldp x19, x20, [sp, #16]
- ldp x21, x22, [sp, #32]
- ldp x23, x24, [sp, #48]
- ldp x25, x26, [sp, #64]
- ldp x27, x28, [sp, #80]
- ldp x29, lr, [sp], #96
+ ldp x29, lr, [sp], #16
+ mov x0, #1
ret
ENDPROC(__cpu_suspend_enter)
.ltorg
@@ -150,12 +120,6 @@ cpu_resume_after_mmu:
bl kasan_unpoison_remaining_stack
#endif
mov x0, #0 // return zero on success
- ldp x19, x20, [sp, #16]
- ldp x21, x22, [sp, #32]
- ldp x23, x24, [sp, #48]
- ldp x25, x26, [sp, #64]
- ldp x27, x28, [sp, #80]
- ldp x29, lr, [sp], #96
ret
ENDPROC(cpu_resume_after_mmu)
@@ -172,6 +136,8 @@ ENTRY(cpu_resume)
/* x7 contains hash index, let's use it to grab context pointer */
ldr_l x0, sleep_save_sp + SLEEP_SAVE_SP_PHYS
ldr x0, [x0, x7, lsl #3]
+ add x29, x0, #SLEEP_STACK_DATA_CALLEE_REGS
+ add x0, x0, #SLEEP_STACK_DATA_SYSTEM_REGS
/* load sp from context */
ldr x2, [x0, #CPU_CTX_SP]
/* load physical address of identity map page table in x1 */
@@ -185,5 +151,12 @@ ENTRY(cpu_resume)
* pointer and x1 to contain physical address of 1:1 page tables
*/
bl cpu_do_resume // PC relative jump, MMU off
+ /* Can't access these by physical address once the MMU is on */
+ ldp x19, x20, [x29, #16]
+ ldp x21, x22, [x29, #32]
+ ldp x23, x24, [x29, #48]
+ ldp x25, x26, [x29, #64]
+ ldp x27, x28, [x29, #80]
+ ldp x29, lr, [x29]
b cpu_resume_mmu // Resume MMU, never returns
ENDPROC(cpu_resume)