arm64: kernel: Add arch-specific SDEI entry code and CPU masking

[mirror_ubuntu-bionic-kernel.git] / arch / arm64 / kernel / entry.S

diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 78647eda6d0d4b12c9246f99ffe1371123927808..bae2daf5d486e2c6cb755e77c9fdd541eacfbb36 100644 (file)
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -1156,3 +1156,104 @@ ENTRY(ret_from_fork)
        b       ret_to_user
 ENDPROC(ret_from_fork)
 NOKPROBE(ret_from_fork)
+
+#ifdef CONFIG_ARM_SDE_INTERFACE
+
+#include <asm/sdei.h>
+#include <uapi/linux/arm_sdei.h>
+
+/*
+ * Software Delegated Exception entry point.
+ *
+ * x0: Event number
+ * x1: struct sdei_registered_event argument from registration time.
+ * x2: interrupted PC
+ * x3: interrupted PSTATE
+ *
+ * Firmware has preserved x0->x17 for us, we must save/restore the rest to
+ * follow SMC-CC. We save (or retrieve) all the registers as the handler may
+ * want them.
+ */
+ENTRY(__sdei_asm_handler)
+       stp     x2, x3, [x1, #SDEI_EVENT_INTREGS + S_PC]
+       stp     x4, x5, [x1, #SDEI_EVENT_INTREGS + 16 * 2]
+       stp     x6, x7, [x1, #SDEI_EVENT_INTREGS + 16 * 3]
+       stp     x8, x9, [x1, #SDEI_EVENT_INTREGS + 16 * 4]
+       stp     x10, x11, [x1, #SDEI_EVENT_INTREGS + 16 * 5]
+       stp     x12, x13, [x1, #SDEI_EVENT_INTREGS + 16 * 6]
+       stp     x14, x15, [x1, #SDEI_EVENT_INTREGS + 16 * 7]
+       stp     x16, x17, [x1, #SDEI_EVENT_INTREGS + 16 * 8]
+       stp     x18, x19, [x1, #SDEI_EVENT_INTREGS + 16 * 9]
+       stp     x20, x21, [x1, #SDEI_EVENT_INTREGS + 16 * 10]
+       stp     x22, x23, [x1, #SDEI_EVENT_INTREGS + 16 * 11]
+       stp     x24, x25, [x1, #SDEI_EVENT_INTREGS + 16 * 12]
+       stp     x26, x27, [x1, #SDEI_EVENT_INTREGS + 16 * 13]
+       stp     x28, x29, [x1, #SDEI_EVENT_INTREGS + 16 * 14]
+       mov     x4, sp
+       stp     lr, x4, [x1, #SDEI_EVENT_INTREGS + S_LR]
+
+       mov     x19, x1
+
+#ifdef CONFIG_VMAP_STACK
+       /*
+        * entry.S may have been using sp as a scratch register, find whether
+        * this is a normal or critical event and switch to the appropriate
+        * stack for this CPU.
+        */
+       ldrb    w4, [x19, #SDEI_EVENT_PRIORITY]
+       cbnz    w4, 1f
+       ldr_this_cpu dst=x5, sym=sdei_stack_normal_ptr, tmp=x6
+       b       2f
+1:     ldr_this_cpu dst=x5, sym=sdei_stack_critical_ptr, tmp=x6
+2:     mov     x6, #SDEI_STACK_SIZE
+       add     x5, x5, x6
+       mov     sp, x5
+#endif
+
+       /*
+        * We may have interrupted userspace, or a guest, or exit-from or
+        * return-to either of these. We can't trust sp_el0, restore it.
+        */
+       mrs     x28, sp_el0
+       ldr_this_cpu    dst=x0, sym=__entry_task, tmp=x1
+       msr     sp_el0, x0
+
+       /* If we interrupted the kernel point to the previous stack/frame. */
+       and     x0, x3, #0xc
+       mrs     x1, CurrentEL
+       cmp     x0, x1
+       csel    x29, x29, xzr, eq       // fp, or zero
+       csel    x4, x2, xzr, eq         // elr, or zero
+
+       stp     x29, x4, [sp, #-16]!
+       mov     x29, sp
+
+       add     x0, x19, #SDEI_EVENT_INTREGS
+       mov     x1, x19
+       bl      __sdei_handler
+
+       msr     sp_el0, x28
+       /* restore regs >x17 that we clobbered */
+       ldp     x28, x29, [x19, #SDEI_EVENT_INTREGS + 16 * 14]
+       ldp     lr, x4, [x19, #SDEI_EVENT_INTREGS + S_LR]
+       mov     sp, x4
+       ldp     x18, x19, [x19, #SDEI_EVENT_INTREGS + 16 * 9]
+
+       mov     x1, x0                  // address to complete_and_resume
+       /* x0 = (x0 <= 1) ? EVENT_COMPLETE:EVENT_COMPLETE_AND_RESUME */
+       cmp     x0, #1
+       mov_q   x2, SDEI_1_0_FN_SDEI_EVENT_COMPLETE
+       mov_q   x3, SDEI_1_0_FN_SDEI_EVENT_COMPLETE_AND_RESUME
+       csel    x0, x2, x3, ls
+
+       /* On success, this call never returns... */
+       ldr_l   x2, sdei_exit_mode
+       cmp     x2, #SDEI_EXIT_SMC
+       b.ne    1f
+       smc     #0
+       b       .
+1:     hvc     #0
+       b       .
+ENDPROC(__sdei_asm_handler)
+NOKPROBE(__sdei_asm_handler)
+#endif /* CONFIG_ARM_SDE_INTERFACE */