[PATCH v2 07/11] arm64: Change cpu_resume() to enable mmu early then access sleep_sp by va
James Morse
james.morse at arm.com
Tue Oct 27 10:29:16 PDT 2015
By enabling the MMU early in cpu_resume(), the sleep_save_sp and stack can
be accessed by VA, which avoids the need to convert-addresses and clean to
PoC on the suspend path.
MMU setup is shared with the boot path, meaning the swapper_pg_dir is
restored directly: ttbr1_el1 is no longer saved/restored.
struct sleep_save_sp is removed, replacing it with a single array of
pointers.
cpu_do_{suspend,resume} could be further reduced to not restore: cpacr_el1,
mdscr_el1, tcr_el1, vbar_el1 and sctlr_el1, all of which are set by
__cpu_setup(). However these values all contain res0 bits that may be used
to enable future features.
Signed-off-by: James Morse <james.morse at arm.com>
---
arch/arm64/include/asm/suspend.h | 7 +----
arch/arm64/kernel/asm-offsets.c | 3 ---
arch/arm64/kernel/head.S | 2 +-
arch/arm64/kernel/setup.c | 1 -
arch/arm64/kernel/sleep.S | 57 ++++++++++++++--------------------------
arch/arm64/kernel/suspend.c | 52 +++---------------------------------
arch/arm64/mm/proc.S | 27 +++++--------------
7 files changed, 33 insertions(+), 116 deletions(-)
diff --git a/arch/arm64/include/asm/suspend.h b/arch/arm64/include/asm/suspend.h
index ccd26da93d03..5faa3ce1fa3a 100644
--- a/arch/arm64/include/asm/suspend.h
+++ b/arch/arm64/include/asm/suspend.h
@@ -1,7 +1,7 @@
#ifndef __ASM_SUSPEND_H
#define __ASM_SUSPEND_H
-#define NR_CTX_REGS 11
+#define NR_CTX_REGS 10
#define NR_CALLEE_SAVED_REGS 12
/*
@@ -17,11 +17,6 @@ struct cpu_suspend_ctx {
u64 sp;
} __aligned(16);
-struct sleep_save_sp {
- phys_addr_t *save_ptr_stash;
- phys_addr_t save_ptr_stash_phys;
-};
-
/*
* Memory to save the cpu state is allocated on the stack by
* __cpu_suspend_enter()'s caller, and populated by __cpu_suspend_enter().
diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c
index 5daa4e692932..3cb1383d3deb 100644
--- a/arch/arm64/kernel/asm-offsets.c
+++ b/arch/arm64/kernel/asm-offsets.c
@@ -157,9 +157,6 @@ int main(void)
DEFINE(CPU_CTX_SP, offsetof(struct cpu_suspend_ctx, sp));
DEFINE(MPIDR_HASH_MASK, offsetof(struct mpidr_hash, mask));
DEFINE(MPIDR_HASH_SHIFTS, offsetof(struct mpidr_hash, shift_aff));
- DEFINE(SLEEP_SAVE_SP_SZ, sizeof(struct sleep_save_sp));
- DEFINE(SLEEP_SAVE_SP_PHYS, offsetof(struct sleep_save_sp, save_ptr_stash_phys));
- DEFINE(SLEEP_SAVE_SP_VIRT, offsetof(struct sleep_save_sp, save_ptr_stash));
DEFINE(SLEEP_STACK_DATA_SYSTEM_REGS, offsetof(struct sleep_stack_data, system_regs));
DEFINE(SLEEP_STACK_DATA_CALLEE_REGS, offsetof(struct sleep_stack_data, callee_saved_regs));
#endif
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index 9ad8b1f15b19..cf4e0bdf6533 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -630,7 +630,7 @@ ENDPROC(__secondary_switched)
* other registers depend on the function called upon completion
*/
.section ".idmap.text", "ax"
-__enable_mmu:
+ENTRY(__enable_mmu)
ldr x5, =vectors
msr vbar_el1, x5
msr ttbr0_el1, x25 // load TTBR0
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index 232247945b1c..5a338235ba1a 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -192,7 +192,6 @@ static void __init smp_build_mpidr_hash(void)
*/
if (mpidr_hash_size() > 4 * num_possible_cpus())
pr_warn("Large number of MPIDR hash buckets detected\n");
- __flush_dcache_area(&mpidr_hash, sizeof(struct mpidr_hash));
}
static void __init setup_processor(void)
diff --git a/arch/arm64/kernel/sleep.S b/arch/arm64/kernel/sleep.S
index 1fa40573db13..07e005d756b0 100644
--- a/arch/arm64/kernel/sleep.S
+++ b/arch/arm64/kernel/sleep.S
@@ -73,8 +73,8 @@ ENTRY(__cpu_suspend_enter)
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]
+ ldr x1, =sleep_save_stash
+ ldr x1, [x1]
mrs x7, mpidr_el1
ldr x9, =mpidr_hash
ldr x10, [x9, #MPIDR_HASH_MASK]
@@ -87,40 +87,26 @@ ENTRY(__cpu_suspend_enter)
compute_mpidr_hash x8, x3, x4, x5, x6, x7, x10
add x1, x1, x8, lsl #3
+ str x0, [x1]
+ add x0, x0, #SLEEP_STACK_DATA_SYSTEM_REGS
push x29, lr
- bl __cpu_suspend_save
+ bl cpu_do_suspend
pop x29, lr
mov x0, #1
ret
ENDPROC(__cpu_suspend_enter)
.ltorg
-/*
- * x0 must contain the sctlr value retrieved from restored context
- */
- .pushsection ".idmap.text", "ax"
-ENTRY(cpu_resume_mmu)
- ldr x3, =cpu_resume_after_mmu
- msr sctlr_el1, x0 // restore sctlr_el1
- isb
- /*
- * Invalidate the local I-cache so that any instructions fetched
- * speculatively from the PoC are discarded, since they may have
- * been dynamically patched at the PoU.
- */
- ic iallu
- dsb nsh
- isb
- br x3 // global jump to virtual address
-ENDPROC(cpu_resume_mmu)
- .popsection
-cpu_resume_after_mmu:
- mov x0, #0 // return zero on success
- ret
-ENDPROC(cpu_resume_after_mmu)
-
ENTRY(cpu_resume)
bl el2_setup // if in EL2 drop to EL1 cleanly
+ /* enable the MMU early - so we can access sleep_save_stash by va */
+ adr_l lr, __enable_mmu /* __cpu_setup will return here */
+ ldr x27, =_cpu_resume /* __enable_mmu will branch here */
+ adrp x25, idmap_pg_dir
+ adrp x26, swapper_pg_dir
+ b __cpu_setup
+
+ENTRY(_cpu_resume)
mrs x1, mpidr_el1
adrp x8, mpidr_hash
add x8, x8, #:lo12:mpidr_hash // x8 = struct mpidr_hash phys address
@@ -130,26 +116,23 @@ ENTRY(cpu_resume)
ldp w5, w6, [x8, #(MPIDR_HASH_SHIFTS + 8)]
compute_mpidr_hash x7, x3, x4, x5, x6, x1, x2
/* x7 contains hash index, let's use it to grab context pointer */
- ldr_l x0, sleep_save_sp + SLEEP_SAVE_SP_PHYS
+ ldr_l x0, sleep_save_stash
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 */
- adrp x1, idmap_pg_dir
mov sp, x2
- /*
- * cpu_do_resume expects x0 to contain context physical address
- * 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 */
+ bl cpu_do_resume
+ msr sctlr_el1, x0
+ isb
+
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
+ mov x0, #0
+ ret
ENDPROC(cpu_resume)
diff --git a/arch/arm64/kernel/suspend.c b/arch/arm64/kernel/suspend.c
index eeb088d15bcb..03ef74c02939 100644
--- a/arch/arm64/kernel/suspend.c
+++ b/arch/arm64/kernel/suspend.c
@@ -11,30 +11,6 @@
/*
- * This is called by __cpu_suspend_enter() to save the state, and do whatever
- * flushing is required to ensure that when the CPU goes to sleep we have
- * the necessary data available when the caches are not searched.
- *
- * ptr: sleep_stack_data containing cpu state virtual address.
- * save_ptr: address of the location where the context physical address
- * must be saved
- */
-void notrace __cpu_suspend_save(struct sleep_stack_data *ptr,
- phys_addr_t *save_ptr)
-{
- *save_ptr = virt_to_phys(ptr);
-
- cpu_do_suspend(&ptr->system_regs);
- /*
- * Only flush the context that must be retrieved with the MMU
- * off. VA primitives ensure the flush is applied to all
- * cache levels so context is pushed to DRAM.
- */
- __flush_dcache_area(ptr, sizeof(*ptr));
- __flush_dcache_area(save_ptr, sizeof(*save_ptr));
-}
-
-/*
* This hook is provided so that cpu_suspend code can restore HW
* breakpoints as early as possible in the resume path, before reenabling
* debug exceptions. Code cannot be run from a CPU PM notifier since by the
@@ -52,21 +28,6 @@ void __init cpu_suspend_set_dbg_restorer(void (*hw_bp_restore)(void *))
void notrace __cpu_suspend_exit(struct mm_struct *mm)
{
- /*
- * We are resuming from reset with TTBR0_EL1 set to the
- * idmap to enable the MMU; set the TTBR0 to the reserved
- * page tables to prevent speculative TLB allocations, flush
- * the local tlb and set the default tcr_el1.t0sz so that
- * the TTBR0 address space set-up is properly restored.
- * If the current active_mm != &init_mm we entered cpu_suspend
- * with mappings in TTBR0 that must be restored, so we switch
- * them back to complete the address space configuration
- * restoration before returning.
- */
- cpu_set_reserved_ttbr0();
- flush_tlb_all();
- cpu_set_default_tcr_t0sz();
-
if (mm != &init_mm)
cpu_switch_mm(mm->pgd, mm);
@@ -138,22 +99,17 @@ int cpu_suspend(unsigned long arg, int (*fn)(unsigned long))
return ret;
}
-struct sleep_save_sp sleep_save_sp;
+unsigned long *sleep_save_stash;
static int __init cpu_suspend_init(void)
{
- void *ctx_ptr;
-
/* ctx_ptr is an array of physical addresses */
- ctx_ptr = kcalloc(mpidr_hash_size(), sizeof(phys_addr_t), GFP_KERNEL);
+ sleep_save_stash = kcalloc(mpidr_hash_size(), sizeof(*sleep_save_stash),
+ GFP_KERNEL);
- if (WARN_ON(!ctx_ptr))
+ if (WARN_ON(!sleep_save_stash))
return -ENOMEM;
- sleep_save_sp.save_ptr_stash = ctx_ptr;
- sleep_save_sp.save_ptr_stash_phys = virt_to_phys(ctx_ptr);
- __flush_dcache_area(&sleep_save_sp, sizeof(struct sleep_save_sp));
-
return 0;
}
early_initcall(cpu_suspend_init);
diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S
index 456c1c5f8ecd..b3afb6123c81 100644
--- a/arch/arm64/mm/proc.S
+++ b/arch/arm64/mm/proc.S
@@ -59,20 +59,17 @@ ENTRY(cpu_do_suspend)
mrs x2, tpidr_el0
mrs x3, tpidrro_el0
mrs x4, contextidr_el1
- mrs x5, mair_el1
mrs x6, cpacr_el1
- mrs x7, ttbr1_el1
mrs x8, tcr_el1
mrs x9, vbar_el1
mrs x10, mdscr_el1
mrs x11, oslsr_el1
mrs x12, sctlr_el1
stp x2, x3, [x0]
- stp x4, x5, [x0, #16]
- stp x6, x7, [x0, #32]
- stp x8, x9, [x0, #48]
- stp x10, x11, [x0, #64]
- str x12, [x0, #80]
+ stp x4, xzr, [x0, #16]
+ stp x6, x8, [x0, #32]
+ stp x9, x10, [x0, #48]
+ stp x11, x12, [x0, #64]
ret
ENDPROC(cpu_do_suspend)
@@ -80,29 +77,20 @@ ENDPROC(cpu_do_suspend)
* cpu_do_resume - restore CPU register context
*
* x0: Physical address of context pointer
- * x1: ttbr0_el1 to be restored
*
* Returns:
* sctlr_el1 value in x0
*/
ENTRY(cpu_do_resume)
- /*
- * Invalidate local tlb entries before turning on MMU
- */
- tlbi vmalle1
ldp x2, x3, [x0]
ldp x4, x5, [x0, #16]
- ldp x6, x7, [x0, #32]
- ldp x8, x9, [x0, #48]
- ldp x10, x11, [x0, #64]
- ldr x12, [x0, #80]
+ ldp x6, x8, [x0, #32]
+ ldp x9, x10, [x0, #48]
+ ldp x11, x12, [x0, #64]
msr tpidr_el0, x2
msr tpidrro_el0, x3
msr contextidr_el1, x4
- msr mair_el1, x5
msr cpacr_el1, x6
- msr ttbr0_el1, x1
- msr ttbr1_el1, x7
tcr_set_idmap_t0sz x8, x7
msr tcr_el1, x8
msr vbar_el1, x9
@@ -113,7 +101,6 @@ ENTRY(cpu_do_resume)
ubfx x11, x11, #1, #1
msr oslar_el1, x11
mov x0, x12
- dsb nsh // Make sure local tlb invalidation completed
isb
ret
ENDPROC(cpu_do_resume)
--
2.1.4
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