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Date: Thu, 2 Aug 2018 15:21:30 +0200
From: Ard Biesheuvel <ard.biesheuvel@...aro.org>
To: kernel-hardening@...ts.openwall.com
Cc: keescook@...omium.org,
christoffer.dall@....com,
will.deacon@....com,
catalin.marinas@....com,
mark.rutland@....com,
labbott@...oraproject.org,
linux-arm-kernel@...ts.infradead.org,
Ard Biesheuvel <ard.biesheuvel@...aro.org>
Subject: [RFC/PoC PATCH 1/3] arm64: use wrapper macro for bl/blx instructions from asm code
In preparation of enabling a feature that temporarily clears the
sign bit in the stack pointer register across a subroutine return,
switch to bl_c/blr_c macros for making such calls from assembler
source. They will be updated in a subsequent patch to conditionally
incorporate the restore sequence for the stack pointer register.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@...aro.org>
---
arch/arm64/include/asm/assembler.h | 12 ++-
arch/arm64/kernel/entry-ftrace.S | 6 +-
arch/arm64/kernel/entry.S | 86 ++++++++++----------
arch/arm64/kernel/head.S | 4 +-
arch/arm64/kernel/probes/kprobes_trampoline.S | 2 +-
arch/arm64/kernel/sleep.S | 6 +-
6 files changed, 62 insertions(+), 54 deletions(-)
diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
index 0bcc98dbba56..346ada4de48a 100644
--- a/arch/arm64/include/asm/assembler.h
+++ b/arch/arm64/include/asm/assembler.h
@@ -687,8 +687,8 @@ USER(\label, ic ivau, \tmp2) // invalidate I line PoU
.endm
.macro do_cond_yield_neon
- bl kernel_neon_end
- bl kernel_neon_begin
+ bl_c kernel_neon_end
+ bl_c kernel_neon_begin
.endm
.macro endif_yield_neon, lbl
@@ -701,4 +701,12 @@ USER(\label, ic ivau, \tmp2) // invalidate I line PoU
.Lyield_out_\@ :
.endm
+ .macro bl_c, target
+ bl \target
+ .endm
+
+ .macro blr_c, reg
+ blr \reg
+ .endm
+
#endif /* __ASM_ASSEMBLER_H */
diff --git a/arch/arm64/kernel/entry-ftrace.S b/arch/arm64/kernel/entry-ftrace.S
index 1175f5827ae1..4691eef0dc65 100644
--- a/arch/arm64/kernel/entry-ftrace.S
+++ b/arch/arm64/kernel/entry-ftrace.S
@@ -106,7 +106,7 @@ ENTRY(_mcount)
mcount_get_pc x0 // function's pc
mcount_get_lr x1 // function's lr (= parent's pc)
- blr x2 // (*ftrace_trace_function)(pc, lr);
+ blr_c x2 // (*ftrace_trace_function)(pc, lr);
skip_ftrace_call: // }
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
@@ -200,7 +200,7 @@ ENTRY(ftrace_graph_caller)
mcount_get_lr_addr x0 // pointer to function's saved lr
mcount_get_pc x1 // function's pc
mcount_get_parent_fp x2 // parent's fp
- bl prepare_ftrace_return // prepare_ftrace_return(&lr, pc, fp)
+ bl_c prepare_ftrace_return // prepare_ftrace_return(&lr, pc, fp)
mcount_exit
ENDPROC(ftrace_graph_caller)
@@ -215,7 +215,7 @@ ENDPROC(ftrace_graph_caller)
ENTRY(return_to_handler)
save_return_regs
mov x0, x29 // parent's fp
- bl ftrace_return_to_handler// addr = ftrace_return_to_hander(fp);
+ bl_c ftrace_return_to_handler// addr = ftrace_return_to_hander(fp);
mov x30, x0 // restore the original return address
restore_return_regs
ret
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 28ad8799406f..eba5b6b528ea 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -43,7 +43,7 @@
*/
.macro ct_user_exit, syscall = 0
#ifdef CONFIG_CONTEXT_TRACKING
- bl context_tracking_user_exit
+ bl_c context_tracking_user_exit
.if \syscall == 1
/*
* Save/restore needed during syscalls. Restore syscall arguments from
@@ -59,7 +59,7 @@
.macro ct_user_enter
#ifdef CONFIG_CONTEXT_TRACKING
- bl context_tracking_user_enter
+ bl_c context_tracking_user_enter
#endif
.endm
@@ -305,7 +305,7 @@ alternative_else_nop_endif
* Cavium erratum 27456 (broadcast TLBI instructions may cause I-cache
* corruption).
*/
- bl post_ttbr_update_workaround
+ bl_c post_ttbr_update_workaround
.endif
1:
.if \el != 0
@@ -425,7 +425,7 @@ tsk .req x28 // current thread_info
ldr_l x1, handle_arch_irq
mov x0, sp
irq_stack_entry
- blr x1
+ blr_c x1
irq_stack_exit
.endm
@@ -490,7 +490,7 @@ __bad_stack:
mov x0, sp
/* Time to die */
- bl handle_bad_stack
+ bl_c handle_bad_stack
ASM_BUG()
#endif /* CONFIG_VMAP_STACK */
@@ -502,7 +502,7 @@ __bad_stack:
mov x0, sp
mov x1, #\reason
mrs x2, esr_el1
- bl bad_mode
+ bl_c bad_mode
ASM_BUG()
.endm
@@ -580,7 +580,7 @@ el1_da:
inherit_daif pstate=x23, tmp=x2
clear_address_tag x0, x3
mov x2, sp // struct pt_regs
- bl do_mem_abort
+ bl_c do_mem_abort
kernel_exit 1
el1_sp_pc:
@@ -590,7 +590,7 @@ el1_sp_pc:
mrs x0, far_el1
inherit_daif pstate=x23, tmp=x2
mov x2, sp
- bl do_sp_pc_abort
+ bl_c do_sp_pc_abort
ASM_BUG()
el1_undef:
/*
@@ -598,7 +598,7 @@ el1_undef:
*/
inherit_daif pstate=x23, tmp=x2
mov x0, sp
- bl do_undefinstr
+ bl_c do_undefinstr
ASM_BUG()
el1_dbg:
/*
@@ -609,7 +609,7 @@ el1_dbg:
tbz x24, #0, el1_inv // EL1 only
mrs x0, far_el1
mov x2, sp // struct pt_regs
- bl do_debug_exception
+ bl_c do_debug_exception
kernel_exit 1
el1_inv:
// TODO: add support for undefined instructions in kernel mode
@@ -617,7 +617,7 @@ el1_inv:
mov x0, sp
mov x2, x1
mov x1, #BAD_SYNC
- bl bad_mode
+ bl_c bad_mode
ASM_BUG()
ENDPROC(el1_sync)
@@ -626,7 +626,7 @@ el1_irq:
kernel_entry 1
enable_da_f
#ifdef CONFIG_TRACE_IRQFLAGS
- bl trace_hardirqs_off
+ bl_c trace_hardirqs_off
#endif
irq_handler
@@ -636,11 +636,11 @@ el1_irq:
cbnz w24, 1f // preempt count != 0
ldr x0, [tsk, #TSK_TI_FLAGS] // get flags
tbz x0, #TIF_NEED_RESCHED, 1f // needs rescheduling?
- bl el1_preempt
+ bl_c el1_preempt
1:
#endif
#ifdef CONFIG_TRACE_IRQFLAGS
- bl trace_hardirqs_on
+ bl_c trace_hardirqs_on
#endif
kernel_exit 1
ENDPROC(el1_irq)
@@ -648,7 +648,7 @@ ENDPROC(el1_irq)
#ifdef CONFIG_PREEMPT
el1_preempt:
mov x24, lr
-1: bl preempt_schedule_irq // irq en/disable is done inside
+1: bl_c preempt_schedule_irq // irq en/disable is done inside
ldr x0, [tsk, #TSK_TI_FLAGS] // get new tasks TI_FLAGS
tbnz x0, #TIF_NEED_RESCHED, 1b // needs rescheduling?
ret x24
@@ -749,7 +749,7 @@ el0_da:
clear_address_tag x0, x26
mov x1, x25
mov x2, sp
- bl do_mem_abort
+ bl_c do_mem_abort
b ret_to_user
el0_ia:
/*
@@ -758,13 +758,13 @@ el0_ia:
mrs x26, far_el1
enable_da_f
#ifdef CONFIG_TRACE_IRQFLAGS
- bl trace_hardirqs_off
+ bl_c trace_hardirqs_off
#endif
ct_user_exit
mov x0, x26
mov x1, x25
mov x2, sp
- bl do_el0_ia_bp_hardening
+ bl_c do_el0_ia_bp_hardening
b ret_to_user
el0_fpsimd_acc:
/*
@@ -774,7 +774,7 @@ el0_fpsimd_acc:
ct_user_exit
mov x0, x25
mov x1, sp
- bl do_fpsimd_acc
+ bl_c do_fpsimd_acc
b ret_to_user
el0_sve_acc:
/*
@@ -784,7 +784,7 @@ el0_sve_acc:
ct_user_exit
mov x0, x25
mov x1, sp
- bl do_sve_acc
+ bl_c do_sve_acc
b ret_to_user
el0_fpsimd_exc:
/*
@@ -794,7 +794,7 @@ el0_fpsimd_exc:
ct_user_exit
mov x0, x25
mov x1, sp
- bl do_fpsimd_exc
+ bl_c do_fpsimd_exc
b ret_to_user
el0_sp_pc:
/*
@@ -803,13 +803,13 @@ el0_sp_pc:
mrs x26, far_el1
enable_da_f
#ifdef CONFIG_TRACE_IRQFLAGS
- bl trace_hardirqs_off
+ bl_c trace_hardirqs_off
#endif
ct_user_exit
mov x0, x26
mov x1, x25
mov x2, sp
- bl do_sp_pc_abort
+ bl_c do_sp_pc_abort
b ret_to_user
el0_undef:
/*
@@ -818,7 +818,7 @@ el0_undef:
enable_daif
ct_user_exit
mov x0, sp
- bl do_undefinstr
+ bl_c do_undefinstr
b ret_to_user
el0_sys:
/*
@@ -828,7 +828,7 @@ el0_sys:
ct_user_exit
mov x0, x25
mov x1, sp
- bl do_sysinstr
+ bl_c do_sysinstr
b ret_to_user
el0_dbg:
/*
@@ -838,7 +838,7 @@ el0_dbg:
mrs x0, far_el1
mov x1, x25
mov x2, sp
- bl do_debug_exception
+ bl_c do_debug_exception
enable_daif
ct_user_exit
b ret_to_user
@@ -848,7 +848,7 @@ el0_inv:
mov x0, sp
mov x1, #BAD_SYNC
mov x2, x25
- bl bad_el0_sync
+ bl_c bad_el0_sync
b ret_to_user
ENDPROC(el0_sync)
@@ -858,19 +858,19 @@ el0_irq:
el0_irq_naked:
enable_da_f
#ifdef CONFIG_TRACE_IRQFLAGS
- bl trace_hardirqs_off
+ bl_c trace_hardirqs_off
#endif
ct_user_exit
#ifdef CONFIG_HARDEN_BRANCH_PREDICTOR
tbz x22, #55, 1f
- bl do_el0_irq_bp_hardening
+ bl_c do_el0_irq_bp_hardening
1:
#endif
irq_handler
#ifdef CONFIG_TRACE_IRQFLAGS
- bl trace_hardirqs_on
+ bl_c trace_hardirqs_on
#endif
b ret_to_user
ENDPROC(el0_irq)
@@ -880,7 +880,7 @@ el1_error:
mrs x1, esr_el1
enable_dbg
mov x0, sp
- bl do_serror
+ bl_c do_serror
kernel_exit 1
ENDPROC(el1_error)
@@ -890,7 +890,7 @@ el0_error_naked:
mrs x1, esr_el1
enable_dbg
mov x0, sp
- bl do_serror
+ bl_c do_serror
enable_daif
ct_user_exit
b ret_to_user
@@ -920,9 +920,9 @@ ret_fast_syscall_trace:
*/
work_pending:
mov x0, sp // 'regs'
- bl do_notify_resume
+ bl_c do_notify_resume
#ifdef CONFIG_TRACE_IRQFLAGS
- bl trace_hardirqs_on // enabled while in userspace
+ bl_c trace_hardirqs_on // enabled while in userspace
#endif
ldr x1, [tsk, #TSK_TI_FLAGS] // re-check for single-step
b finish_ret_to_user
@@ -980,11 +980,11 @@ el0_svc_naked: // compat entry point
b.hs ni_sys
mask_nospec64 xscno, xsc_nr, x19 // enforce bounds for syscall number
ldr x16, [stbl, xscno, lsl #3] // address in the syscall table
- blr x16 // call sys_* routine
+ blr_c x16 // call sys_* routine
b ret_fast_syscall
ni_sys:
mov x0, sp
- bl do_ni_syscall
+ bl_c do_ni_syscall
b ret_fast_syscall
ENDPROC(el0_svc)
@@ -998,7 +998,7 @@ __sys_trace:
mov x0, #-ENOSYS // set default errno if so
str x0, [sp, #S_X0]
1: mov x0, sp
- bl syscall_trace_enter
+ bl_c syscall_trace_enter
cmp w0, #NO_SYSCALL // skip the syscall?
b.eq __sys_trace_return_skipped
mov wscno, w0 // syscall number (possibly new)
@@ -1010,18 +1010,18 @@ __sys_trace:
ldp x4, x5, [sp, #S_X4]
ldp x6, x7, [sp, #S_X6]
ldr x16, [stbl, xscno, lsl #3] // address in the syscall table
- blr x16 // call sys_* routine
+ blr_c x16 // call sys_* routine
__sys_trace_return:
str x0, [sp, #S_X0] // save returned x0
__sys_trace_return_skipped:
mov x0, sp
- bl syscall_trace_exit
+ bl_c syscall_trace_exit
b ret_to_user
__ni_sys_trace:
mov x0, sp
- bl do_ni_syscall
+ bl_c do_ni_syscall
b __sys_trace_return
.popsection // .entry.text
@@ -1182,10 +1182,10 @@ NOKPROBE(cpu_switch_to)
* This is how we return from a fork.
*/
ENTRY(ret_from_fork)
- bl schedule_tail
+ bl_c schedule_tail
cbz x19, 1f // not a kernel thread
mov x0, x20
- blr x19
+ blr_c x19
1: get_thread_info tsk
b ret_to_user
ENDPROC(ret_from_fork)
@@ -1337,7 +1337,7 @@ ENTRY(__sdei_asm_handler)
add x0, x19, #SDEI_EVENT_INTREGS
mov x1, x19
- bl __sdei_handler
+ bl_c __sdei_handler
msr sp_el0, x28
/* restore regs >x17 that we clobbered */
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index b0853069702f..10414bbbeecb 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -432,13 +432,13 @@ __primary_switched:
dsb ishst // Make zero page visible to PTW
#ifdef CONFIG_KASAN
- bl kasan_early_init
+ bl_c kasan_early_init
#endif
#ifdef CONFIG_RANDOMIZE_BASE
tst x23, ~(MIN_KIMG_ALIGN - 1) // already running randomized?
b.ne 0f
mov x0, x21 // pass FDT address in x0
- bl kaslr_early_init // parse FDT for KASLR options
+ bl_c kaslr_early_init // parse FDT for KASLR options
cbz x0, 0f // KASLR disabled? just proceed
orr x23, x23, x0 // record KASLR offset
ldp x29, x30, [sp], #16 // we must enable KASLR, return
diff --git a/arch/arm64/kernel/probes/kprobes_trampoline.S b/arch/arm64/kernel/probes/kprobes_trampoline.S
index 45dce03aaeaf..0b195b727dc7 100644
--- a/arch/arm64/kernel/probes/kprobes_trampoline.S
+++ b/arch/arm64/kernel/probes/kprobes_trampoline.S
@@ -67,7 +67,7 @@ ENTRY(kretprobe_trampoline)
save_all_base_regs
mov x0, sp
- bl trampoline_probe_handler
+ bl_c trampoline_probe_handler
/*
* Replace trampoline address in lr with actual orig_ret_addr return
* address.
diff --git a/arch/arm64/kernel/sleep.S b/arch/arm64/kernel/sleep.S
index bebec8ef9372..6ced3a8bb528 100644
--- a/arch/arm64/kernel/sleep.S
+++ b/arch/arm64/kernel/sleep.S
@@ -90,7 +90,7 @@ ENTRY(__cpu_suspend_enter)
str x0, [x1]
add x0, x0, #SLEEP_STACK_DATA_SYSTEM_REGS
stp x29, lr, [sp, #-16]!
- bl cpu_do_suspend
+ bl_c cpu_do_suspend
ldp x29, lr, [sp], #16
mov x0, #1
ret
@@ -129,11 +129,11 @@ ENTRY(_cpu_resume)
/*
* cpu_do_resume expects x0 to contain context address pointer
*/
- bl cpu_do_resume
+ bl_c cpu_do_resume
#ifdef CONFIG_KASAN
mov x0, sp
- bl kasan_unpoison_task_stack_below
+ bl_c kasan_unpoison_task_stack_below
#endif
ldp x19, x20, [x29, #16]
--
2.18.0
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