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Subject[PATCH v6 19/33] arm64: Annotate unwind_hint for symbols with empty stack
Date
Some assembly symbols contain code that might be executed with an
unspecified stack state (e.g. invalid stack pointer,
no stackframe, code after alt_cb, ...).

Annotate those symbol with UNWIND_HINT_EMPTY to let objtool be aware of
them.

Signed-off-by: Julien Thierry <jthierry@redhat.com>
Signed-off-by: Chen Zhongjin <chenzhongjin@huawei.com>
---
arch/arm64/include/asm/assembler.h | 2 ++
arch/arm64/kernel/cpu-reset.S | 2 ++
arch/arm64/kernel/efi-entry.S | 2 ++
arch/arm64/kernel/entry.S | 7 +++++++
arch/arm64/kernel/head.S | 14 ++++++++++++++
arch/arm64/kernel/hibernate-asm.S | 2 ++
arch/arm64/kernel/relocate_kernel.S | 2 ++
arch/arm64/kernel/sleep.S | 3 +++
arch/arm64/kvm/hyp/hyp-entry.S | 1 +
arch/arm64/mm/trans_pgd-asm.S | 3 +++
10 files changed, 38 insertions(+)

diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
index 8c5a61aeaf8e..68db05428e4b 100644
--- a/arch/arm64/include/asm/assembler.h
+++ b/arch/arm64/include/asm/assembler.h
@@ -25,6 +25,7 @@
#include <asm/pgtable-hwdef.h>
#include <asm/ptrace.h>
#include <asm/thread_info.h>
+#include <asm/unwind_hints.h>

/*
* Provide a wxN alias for each wN register so what we can paste a xN
@@ -147,6 +148,7 @@ lr .req x30 // link register
*/
.macro ventry label
.align 7
+ UNWIND_HINT_EMPTY
b \label
.endm

diff --git a/arch/arm64/kernel/cpu-reset.S b/arch/arm64/kernel/cpu-reset.S
index 48a8af97faa9..c9022042bdec 100644
--- a/arch/arm64/kernel/cpu-reset.S
+++ b/arch/arm64/kernel/cpu-reset.S
@@ -10,6 +10,7 @@
#include <linux/linkage.h>
#include <asm/assembler.h>
#include <asm/sysreg.h>
+#include <asm/unwind_hints.h>
#include <asm/virt.h>

.text
@@ -29,6 +30,7 @@
* flat identity mapping.
*/
SYM_CODE_START(cpu_soft_restart)
+ UNWIND_HINT_EMPTY
mov_q x12, INIT_SCTLR_EL1_MMU_OFF
pre_disable_mmu_workaround
/*
diff --git a/arch/arm64/kernel/efi-entry.S b/arch/arm64/kernel/efi-entry.S
index 61a87fa1c305..9a1a94c3c4db 100644
--- a/arch/arm64/kernel/efi-entry.S
+++ b/arch/arm64/kernel/efi-entry.S
@@ -9,10 +9,12 @@
#include <linux/init.h>

#include <asm/assembler.h>
+#include <asm/unwind_hints.h>

__INIT

SYM_CODE_START(efi_enter_kernel)
+ UNWIND_HINT_EMPTY
/*
* efi_pe_entry() will have copied the kernel image if necessary and we
* end up here with device tree address in x1 and the kernel entry
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index c460ba2d009d..3bd11101e79d 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -28,6 +28,7 @@
#include <asm/thread_info.h>
#include <asm/asm-uaccess.h>
#include <asm/unistd.h>
+#include <asm/unwind_hints.h>

.macro clear_gp_regs
.irp n,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29
@@ -37,6 +38,7 @@

.macro kernel_ventry, el:req, ht:req, regsize:req, label:req
.align 7
+ UNWIND_HINT_EMPTY
.Lventry_start\@:
.if \el == 0
/*
@@ -44,6 +46,7 @@
* skipped by the trampoline vectors, to trigger the cleanup.
*/
b .Lskip_tramp_vectors_cleanup\@
+ UNWIND_HINT_EMPTY
.if \regsize == 64
mrs x30, tpidrro_el0
msr tpidrro_el0, xzr
@@ -417,6 +420,7 @@ alternative_else_nop_endif
ldp x24, x25, [sp, #16 * 12]
ldp x26, x27, [sp, #16 * 13]
ldp x28, x29, [sp, #16 * 14]
+ UNWIND_HINT_EMPTY

.if \el == 0
alternative_if_not ARM64_UNMAP_KERNEL_AT_EL0
@@ -662,6 +666,7 @@ alternative_else_nop_endif

.macro tramp_ventry, vector_start, regsize, kpti, bhb
.align 7
+ UNWIND_HINT_EMPTY
1:
.if \regsize == 64
msr tpidrro_el0, x30 // Restored in kernel_ventry
@@ -687,6 +692,7 @@ alternative_else_nop_endif
* enter the full-fat kernel vectors.
*/
bl 2f
+ UNWIND_HINT_EMPTY
b .
2:
tramp_map_kernel x30
@@ -717,6 +723,7 @@ alternative_else_nop_endif
.endm

.macro tramp_exit, regsize = 64
+ UNWIND_HINT_EMPTY
tramp_data_read_var x30, this_cpu_vector
get_this_cpu_offset x29
ldr x30, [x30, x29]
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index 6db9c3603bd8..2a66d18091eb 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -33,6 +33,7 @@
#include <asm/smp.h>
#include <asm/sysreg.h>
#include <asm/thread_info.h>
+#include <asm/unwind_hints.h>
#include <asm/virt.h>

#include "efi-header.S"
@@ -63,6 +64,7 @@
* DO NOT MODIFY. Image header expected by Linux boot-loaders.
*/
efi_signature_nop // special NOP to identity as PE/COFF executable
+ UNWIND_HINT_EMPTY
b primary_entry // branch to kernel start, magic
.quad 0 // Image load offset from start of RAM, little-endian
le64sym _kernel_size_le // Effective size of kernel image, little-endian
@@ -109,6 +111,7 @@ SYM_CODE_END(primary_entry)
* Preserve the arguments passed by the bootloader in x0 .. x3
*/
SYM_CODE_START_LOCAL(preserve_boot_args)
+ UNWIND_HINT_EMPTY
mov x21, x0 // x21=FDT

adr_l x0, boot_args // record the contents of
@@ -260,6 +263,7 @@ SYM_CODE_END(preserve_boot_args)
* been enabled
*/
SYM_CODE_START_LOCAL(__create_page_tables)
+ UNWIND_HINT_EMPTY
mov x28, lr

/*
@@ -494,6 +498,7 @@ EXPORT_SYMBOL(kimage_vaddr)
* booted in EL1 or EL2 respectively.
*/
SYM_CODE_START(init_kernel_el)
+ UNWIND_HINT_EMPTY
mrs x0, CurrentEL
cmp x0, #CurrentEL_EL2
b.eq init_el2
@@ -553,6 +558,7 @@ SYM_INNER_LABEL(init_el2, SYM_L_LOCAL)
eret

__cpu_stick_to_vhe:
+ UNWIND_HINT_EMPTY
mov x0, #HVC_VHE_RESTART
hvc #0
mov x0, #BOOT_CPU_MODE_EL2
@@ -564,6 +570,7 @@ SYM_CODE_END(init_kernel_el)
* in w0. See arch/arm64/include/asm/virt.h for more info.
*/
SYM_CODE_START_LOCAL(set_cpu_boot_mode_flag)
+ UNWIND_HINT_EMPTY
adr_l x1, __boot_cpu_mode
cmp w0, #BOOT_CPU_MODE_EL2
b.ne 1f
@@ -607,6 +614,7 @@ SYM_DATA_END(__early_cpu_boot_status)
* cores are held until we're ready for them to initialise.
*/
SYM_CODE_START(secondary_holding_pen)
+ UNWIND_HINT_EMPTY
bl init_kernel_el // w0=cpu_boot_mode
bl set_cpu_boot_mode_flag
mrs x0, mpidr_el1
@@ -625,6 +633,7 @@ SYM_CODE_END(secondary_holding_pen)
* be used where CPUs are brought online dynamically by the kernel.
*/
SYM_CODE_START(secondary_entry)
+ UNWIND_HINT_EMPTY
bl init_kernel_el // w0=cpu_boot_mode
bl set_cpu_boot_mode_flag
b secondary_startup
@@ -644,6 +653,7 @@ SYM_CODE_START_LOCAL(secondary_startup)
SYM_CODE_END(secondary_startup)

SYM_CODE_START_LOCAL(__secondary_switched)
+ UNWIND_HINT_EMPTY
adr_l x5, vectors
msr vbar_el1, x5
isb
@@ -663,6 +673,7 @@ SYM_CODE_START_LOCAL(__secondary_switched)
SYM_CODE_END(__secondary_switched)

SYM_CODE_START_LOCAL(__secondary_too_slow)
+ UNWIND_HINT_EMPTY
wfe
wfi
b __secondary_too_slow
@@ -699,6 +710,7 @@ SYM_CODE_END(__secondary_too_slow)
* If it isn't, park the CPU
*/
SYM_CODE_START(__enable_mmu)
+ UNWIND_HINT_EMPTY
mrs x2, ID_AA64MMFR0_EL1
ubfx x2, x2, #ID_AA64MMFR0_TGRAN_SHIFT, 4
cmp x2, #ID_AA64MMFR0_TGRAN_SUPPORTED_MIN
@@ -720,6 +732,7 @@ SYM_CODE_START(__enable_mmu)
SYM_CODE_END(__enable_mmu)

SYM_CODE_START_LOCAL(__cpu_secondary_check52bitva)
+ UNWIND_HINT_EMPTY
#ifdef CONFIG_ARM64_VA_BITS_52
ldr_l x0, vabits_actual
cmp x0, #52
@@ -751,6 +764,7 @@ SYM_CODE_END(__no_granule_support)

#ifdef CONFIG_RELOCATABLE
SYM_CODE_START_LOCAL(__relocate_kernel)
+ UNWIND_HINT_EMPTY
/*
* Iterate over each entry in the relocation table, and apply the
* relocations in place.
diff --git a/arch/arm64/kernel/hibernate-asm.S b/arch/arm64/kernel/hibernate-asm.S
index 0e1d9c3c6a93..c0bec20bf0e0 100644
--- a/arch/arm64/kernel/hibernate-asm.S
+++ b/arch/arm64/kernel/hibernate-asm.S
@@ -13,6 +13,7 @@
#include <asm/cputype.h>
#include <asm/memory.h>
#include <asm/page.h>
+#include <asm/unwind_hints.h>
#include <asm/virt.h>

/*
@@ -46,6 +47,7 @@
*/
.pushsection ".hibernate_exit.text", "ax"
SYM_CODE_START(swsusp_arch_suspend_exit)
+ UNWIND_HINT_EMPTY
/*
* We execute from ttbr0, change ttbr1 to our copied linear map tables
* with a break-before-make via the zero page
diff --git a/arch/arm64/kernel/relocate_kernel.S b/arch/arm64/kernel/relocate_kernel.S
index f0a3df9e18a3..f8cd8fcf2d4f 100644
--- a/arch/arm64/kernel/relocate_kernel.S
+++ b/arch/arm64/kernel/relocate_kernel.S
@@ -16,6 +16,7 @@
#include <asm/page.h>
#include <asm/sysreg.h>
#include <asm/virt.h>
+#include <asm/unwind_hints.h>

.macro turn_off_mmu tmp1, tmp2
mov_q \tmp1, INIT_SCTLR_EL1_MMU_OFF
@@ -37,6 +38,7 @@
* safe memory that has been set up to be preserved during the copy operation.
*/
SYM_CODE_START(arm64_relocate_new_kernel)
+ UNWIND_HINT_EMPTY
/* Setup the list loop variables. */
ldr x18, [x0, #KIMAGE_ARCH_ZERO_PAGE] /* x18 = zero page for BBM */
ldr x17, [x0, #KIMAGE_ARCH_TTBR1] /* x17 = linear map copy */
diff --git a/arch/arm64/kernel/sleep.S b/arch/arm64/kernel/sleep.S
index f0087e8bcd28..799ec01b0649 100644
--- a/arch/arm64/kernel/sleep.S
+++ b/arch/arm64/kernel/sleep.S
@@ -4,6 +4,7 @@
#include <asm/asm-offsets.h>
#include <asm/assembler.h>
#include <asm/smp.h>
+#include <asm/unwind_hints.h>

.text
/*
@@ -99,6 +100,7 @@ SYM_FUNC_END(__cpu_suspend_enter)

.pushsection ".idmap.text", "awx"
SYM_CODE_START(cpu_resume)
+ UNWIND_HINT_EMPTY
bl init_kernel_el
bl switch_to_vhe
bl __cpu_setup
@@ -112,6 +114,7 @@ SYM_CODE_END(cpu_resume)
.popsection

SYM_CODE_START(_cpu_resume)
+ UNWIND_HINT_EMPTY
mrs x1, mpidr_el1
adr_l x8, mpidr_hash // x8 = struct mpidr_hash virt address

diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S
index 7839d075729b..4a65262a4f3a 100644
--- a/arch/arm64/kvm/hyp/hyp-entry.S
+++ b/arch/arm64/kvm/hyp/hyp-entry.S
@@ -14,6 +14,7 @@
#include <asm/kvm_asm.h>
#include <asm/mmu.h>
#include <asm/spectre.h>
+#include <asm/unwind_hints.h>

.macro save_caller_saved_regs_vect
/* x0 and x1 were saved in the vector entry */
diff --git a/arch/arm64/mm/trans_pgd-asm.S b/arch/arm64/mm/trans_pgd-asm.S
index 021c31573bcb..148435248860 100644
--- a/arch/arm64/mm/trans_pgd-asm.S
+++ b/arch/arm64/mm/trans_pgd-asm.S
@@ -8,10 +8,12 @@
#include <linux/linkage.h>
#include <asm/assembler.h>
#include <asm/kvm_asm.h>
+#include <asm/unwind_hints.h>

.macro invalid_vector label
SYM_CODE_START_LOCAL(\label)
.align 7
+ UNWIND_HINT_EMPTY
b \label
SYM_CODE_END(\label)
.endm
@@ -19,6 +21,7 @@ SYM_CODE_END(\label)
.macro el1_sync_vector
SYM_CODE_START_LOCAL(el1_sync)
.align 7
+ UNWIND_HINT_EMPTY
cmp x0, #HVC_SET_VECTORS /* Called from hibernate */
b.ne 1f
msr vbar_el2, x1
--
2.17.1
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