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-rw-r--r--arch/arm/kernel/entry-header.S25
1 files changed, 25 insertions, 0 deletions
diff --git a/arch/arm/kernel/entry-header.S b/arch/arm/kernel/entry-header.S
index 0f07579af472c..773424843d6ef 100644
--- a/arch/arm/kernel/entry-header.S
+++ b/arch/arm/kernel/entry-header.S
@@ -378,6 +378,31 @@
#endif
.endm
+ .macro invoke_syscall, table, nr, tmp, ret, reload=0
+#ifdef CONFIG_CPU_SPECTRE
+ mov \tmp, \nr
+ cmp \tmp, #NR_syscalls @ check upper syscall limit
+ movcs \tmp, #0
+ csdb
+ badr lr, \ret @ return address
+ .if \reload
+ add r1, sp, #S_R0 + S_OFF @ pointer to regs
+ ldmccia r1, {r0 - r6} @ reload r0-r6
+ stmccia sp, {r4, r5} @ update stack arguments
+ .endif
+ ldrcc pc, [\table, \tmp, lsl #2] @ call sys_* routine
+#else
+ cmp \nr, #NR_syscalls @ check upper syscall limit
+ badr lr, \ret @ return address
+ .if \reload
+ add r1, sp, #S_R0 + S_OFF @ pointer to regs
+ ldmccia r1, {r0 - r6} @ reload r0-r6
+ stmccia sp, {r4, r5} @ update stack arguments
+ .endif
+ ldrcc pc, [\table, \nr, lsl #2] @ call sys_* routine
+#endif
+ .endm
+
/*
* These are the registers used in the syscall handler, and allow us to
* have in theory up to 7 arguments to a function - r0 to r6.