el1_sync unmasks exceptions on a case-by-case basis, debug exceptions
are unmasked, unless this was a debug exception. IRQs are unmasked
for instruction and data aborts only if the interrupted context had
irqs unmasked.
Following our 'adi' order, el1_dbg should run with Debug and Interrupt
exceptions masked. For the other cases we can inherit whatever we
interrupted.
Add a macro inherit_daif to set daif based on the interrupted pstate.
el0_sync also unmasks exceptions on a case-by-case basis, debug exceptions
are unmasked, unless this was a debug exception. Irqs are unmasked for
some exception types but not for others.
el0_dbg should run with Debug and Interrupt exceptions masked, for the
other cases we can unmask everything. This changes the behaviour of
fpsimd_{acc,exc} and el0_inv, which previously ran with Interrupts masked.
All of these el0 exception types call ct_user_exit after unmasking IRQs.
Move this into the switch statement. el0_dbg needs to do this itself once
it has finished its work and el0_svc needs to pass a flag to restore the
syscall args.
This patch removed the last user of enable_dbg_and_irq, remove it.
Signed-off-by: James Morse <james.morse@xxxxxxx>
---
arch/arm64/include/asm/assembler.h | 19 +++++------
arch/arm64/kernel/entry.S | 66 +++++++++++++-------------------------
2 files changed, 33 insertions(+), 52 deletions(-)
diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
index f4dc435406ea..6a2512da468a 100644
--- a/arch/arm64/include/asm/assembler.h
+++ b/arch/arm64/include/asm/assembler.h
@@ -50,6 +50,12 @@
msr daif, \flags
.endm
+ /* Only on aarch64 pstate, PSR_D_BIT is different for aarch32 */
+ .macro inherit_daif, pstate:req, tmp:req
+ and \tmp, \pstate, #(PSR_D_BIT | PSR_A_BIT | PSR_I_BIT | PSR_F_BIT)
+ msr daif, \tmp
+ .endm
+
/*
* Enable and disable interrupts.
*/
@@ -70,6 +76,10 @@
msr daif, \flags
.endm
+ .macro enable_serror
+ msr daifclr, #4
+ .endm
+
.macro enable_dbg
msr daifclr, #8
.endm
@@ -93,15 +103,6 @@
.endm
/*
- * Enable both debug exceptions and interrupts. This is likely to be
- * faster than two daifclr operations, since writes to this register
- * are self-synchronising.
- */
- .macro enable_dbg_and_irq
- msr daifclr, #(8 | 2)
- .endm
-
-/*
* SMP data memory barrier
*/
.macro smp_dmb, opt
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 0836b65d4c84..51e704e46c29 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -408,8 +408,13 @@ ENDPROC(el1_error_invalid)
.align 6
el1_sync:
kernel_entry 1
+ mrs x0, far_el1
mrs x1, esr_el1 // read the syndrome register
lsr x24, x1, #ESR_ELx_EC_SHIFT // exception class
+ cmp x24, #ESR_ELx_EC_BREAKPT_CUR // debug exception in EL1
+ b.ge el1_dbg
+
+ inherit_daif pstate=x23, tmp=x2
cmp x24, #ESR_ELx_EC_DABT_CUR // data abort in EL1
b.eq el1_da
cmp x24, #ESR_ELx_EC_IABT_CUR // instruction abort in EL1
@@ -422,8 +427,6 @@ el1_sync:
b.eq el1_sp_pc
cmp x24, #ESR_ELx_EC_UNKNOWN // unknown exception in EL1
b.eq el1_undef
- cmp x24, #ESR_ELx_EC_BREAKPT_CUR // debug exception in EL1
- b.ge el1_dbg
b el1_inv
el1_ia:
@@ -434,12 +437,7 @@ el1_da:
/*
* Data abort handling
*/
- mrs x3, far_el1
- enable_dbg
- // re-enable interrupts if they were enabled in the aborted context
- tbnz x23, #7, 1f // PSR_I_BIT
- enable_irq
-1:
+ mov x3, x0
clear_address_tag x0, x3
mov x2, sp // struct pt_regs
bl do_mem_abort
@@ -449,31 +447,27 @@ el1_sp_pc:
/*
* Stack or PC alignment exception handling
*/
- mrs x0, far_el1
- enable_dbg
mov x2, sp
b do_sp_pc_abort
el1_undef:
/*
* Undefined instruction
*/
- enable_dbg
mov x0, sp
b do_undefinstr
el1_dbg:
/*
* Debug exception handling
*/
+ enable_serror
cmp x24, #ESR_ELx_EC_BRK64 // if BRK64
cinc x24, x24, eq // set bit '0'
tbz x24, #0, el1_inv // EL1 only
- mrs x0, far_el1
mov x2, sp // struct pt_regs
bl do_debug_exception
kernel_exit 1
el1_inv:
// TODO: add support for undefined instructions in kernel mode
- enable_dbg
mov x0, sp
mov x2, x1
mov x1, #BAD_SYNC
@@ -520,9 +514,16 @@ el1_preempt:
el0_sync:
kernel_entry 0
mrs x25, esr_el1 // read the syndrome register
+ mrs x26, far_el1
lsr x24, x25, #ESR_ELx_EC_SHIFT // exception class
+ cmp x24, #ESR_ELx_EC_BREAKPT_LOW // debug exception in EL0
+ b.ge el0_dbg
+
+ enable_daif
cmp x24, #ESR_ELx_EC_SVC64 // SVC in 64-bit state
b.eq el0_svc
+
+ ct_user_exit
cmp x24, #ESR_ELx_EC_DABT_LOW // data abort in EL0
b.eq el0_da
cmp x24, #ESR_ELx_EC_IABT_LOW // instruction abort in EL0
@@ -539,8 +540,6 @@ el0_sync:
b.eq el0_sp_pc
cmp x24, #ESR_ELx_EC_UNKNOWN // unknown exception in EL0
b.eq el0_undef
- cmp x24, #ESR_ELx_EC_BREAKPT_LOW // debug exception in EL0
- b.ge el0_dbg
b el0_inv
#ifdef CONFIG_COMPAT
@@ -548,9 +547,16 @@ el0_sync:
el0_sync_compat:
kernel_entry 0, 32
mrs x25, esr_el1 // read the syndrome register
+ mrs x26, far_el1
lsr x24, x25, #ESR_ELx_EC_SHIFT // exception class
+ cmp x24, #ESR_ELx_EC_BREAKPT_LOW // debug exception in EL0
+ b.ge el0_dbg
+
+ enable_daif
cmp x24, #ESR_ELx_EC_SVC32 // SVC in 32-bit state
b.eq el0_svc_compat
+
+ ct_user_exit
cmp x24, #ESR_ELx_EC_DABT_LOW // data abort in EL0
b.eq el0_da
cmp x24, #ESR_ELx_EC_IABT_LOW // instruction abort in EL0
@@ -573,8 +579,6 @@ el0_sync_compat:
b.eq el0_undef
cmp x24, #ESR_ELx_EC_CP14_64 // CP14 MRRC/MCRR trap
b.eq el0_undef
- cmp x24, #ESR_ELx_EC_BREAKPT_LOW // debug exception in EL0
- b.ge el0_dbg
b el0_inv
el0_svc_compat:
/*
@@ -595,10 +599,6 @@ el0_da:
/*
* Data abort handling
*/
- mrs x26, far_el1
- // enable interrupts before calling the main handler
- enable_dbg_and_irq
- ct_user_exit
clear_address_tag x0, x26
mov x1, x25
mov x2, sp
@@ -608,10 +608,6 @@ el0_ia:
/*
* Instruction abort handling
*/
- mrs x26, far_el1
- // enable interrupts before calling the main handler
- enable_dbg_and_irq
- ct_user_exit
mov x0, x26
mov x1, x25
mov x2, sp
@@ -621,8 +617,6 @@ el0_fpsimd_acc:
/*
* Floating Point or Advanced SIMD access
*/
- enable_dbg
- ct_user_exit
mov x0, x25
mov x1, sp
bl do_fpsimd_acc
@@ -631,8 +625,6 @@ el0_fpsimd_exc:
/*
* Floating Point or Advanced SIMD exception
*/
- enable_dbg
- ct_user_exit
mov x0, x25
mov x1, sp
bl do_fpsimd_exc
@@ -641,10 +633,6 @@ el0_sp_pc:
/*
* Stack or PC alignment exception handling
*/
- mrs x26, far_el1
- // enable interrupts before calling the main handler
- enable_dbg_and_irq
- ct_user_exit
mov x0, x26
mov x1, x25
mov x2, sp
@@ -654,9 +642,6 @@ el0_undef:
/*
* Undefined instruction
*/
- // enable interrupts before calling the main handler
- enable_dbg_and_irq
- ct_user_exit
mov x0, sp
bl do_undefinstr
b ret_to_user
@@ -664,8 +649,6 @@ el0_sys:
/*
* System instructions, for trapped cache maintenance instructions
*/
- enable_dbg_and_irq
- ct_user_exit
mov x0, x25
mov x1, sp
bl do_sysinstr
@@ -675,16 +658,14 @@ el0_dbg:
* Debug exception handling
*/
tbnz x24, #0, el0_inv // EL0 only
- mrs x0, far_el1
+ mov x0, x26
mov x1, x25
mov x2, sp
bl do_debug_exception
- enable_dbg
+ enable_daif
ct_user_exit
b ret_to_user
el0_inv:
- enable_dbg
- ct_user_exit
mov x0, sp
mov x1, #BAD_SYNC
mov x2, x25
@@ -803,7 +784,6 @@ el0_svc:
mov sc_nr, #__NR_syscalls
el0_svc_naked: // compat entry point
stp x0, scno, [sp, #S_ORIG_X0] // save the original x0 and syscall number
- enable_dbg_and_irq
ct_user_exit 1
ldr x16, [tsk, #TSK_TI_FLAGS] // check for syscall hooks
--
2.13.2
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