File 5dbafbfd-Arm32-entry-fold-SAVE_ALL-into-vector-... of Package xen.20938

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File 5dbafbfd-Arm32-entry-fold-SAVE_ALL-into-vector-macro.patch of Package xen.20938

# Commit a7b81b021ead23bffb5affcac05edfc0a84d129d
# Date 2019-10-31 16:21:33 +0100
# Author Julien Grall <julien.grall@arm.com>
# Committer Jan Beulich <jbeulich@suse.com>
xen/arm32: entry: Fold the macro SAVE_ALL in the macro vector

Follow-up rework will require the macro vector to distinguish between
a trap from a guest vs while in the hypervisor.

The macro SAVE_ALL already has code to distinguish between the two and
it is only called by the vector macro. So fold the former into the
latter. This will help to avoid duplicating the check.

This is part of XSA-303.

Reported-by: Julien Grall <Julien.Grall@arm.com>
Signed-off-by: Julien Grall <julien.grall@arm.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>

--- a/xen/arch/arm/arm32/entry.S
+++ b/xen/arch/arm/arm32/entry.S
@@ -12,27 +12,6 @@
 #define RESTORE_BANKED(mode) \
         RESTORE_ONE_BANKED(SP_##mode) ; RESTORE_ONE_BANKED(LR_##mode) ; RESTORE_ONE_BANKED(SPSR_##mode)
 
-#define SAVE_ALL                                                        \
-        sub sp, #(UREGS_SP_usr - UREGS_sp); /* SP, LR, SPSR, PC */      \
-        push {r0-r12}; /* Save R0-R12 */                                \
-                                                                        \
-        mrs r11, ELR_hyp;               /* ELR_hyp is return address. */\
-        str r11, [sp, #UREGS_pc];                                       \
-                                                                        \
-        str lr, [sp, #UREGS_lr];                                        \
-                                                                        \
-        add r11, sp, #UREGS_kernel_sizeof+4;                            \
-        str r11, [sp, #UREGS_sp];                                       \
-                                                                        \
-        mrc CP32(r11, HSR);             /* Save exception syndrome */   \
-        str r11, [sp, #UREGS_hsr];                                      \
-                                                                        \
-        mrs r11, SPSR_hyp;                                              \
-        str r11, [sp, #UREGS_cpsr];                                     \
-        and r11, #PSR_MODE_MASK;                                        \
-        cmp r11, #PSR_MODE_HYP;                                         \
-        blne save_guest_regs
-
 save_guest_regs:
 #ifdef CONFIG_ARM32_HARDEN_BRANCH_PREDICTOR
         /*
@@ -51,7 +30,7 @@ save_guest_regs:
         ldr r11, =0xffffffff  /* Clobber SP which is only valid for hypervisor frames. */
         str r11, [sp, #UREGS_sp]
         SAVE_ONE_BANKED(SP_usr)
-        /* LR_usr is the same physical register as lr and is saved in SAVE_ALL */
+        /* LR_usr is the same physical register as lr and is saved by the caller */
         SAVE_BANKED(svc)
         SAVE_BANKED(abt)
         SAVE_BANKED(und)
@@ -130,7 +109,28 @@ skip_check:
          * interrupts (Asynchronous Abort, IRQ, FIQ) to unmask.
          */
         .macro vector trap, iflags
-        SAVE_ALL
+        /* Save registers in the stack */
+        sub     sp, #(UREGS_SP_usr - UREGS_sp) /* SP, LR, SPSR, PC */
+        push    {r0-r12}                       /* Save R0-R12 */
+        mrs     r11, ELR_hyp                   /* ELR_hyp is return address */
+        str     r11, [sp, #UREGS_pc]
+
+        str     lr, [sp, #UREGS_lr]
+
+        add     r11, sp, #(UREGS_kernel_sizeof + 4)
+
+        str     r11, [sp, #UREGS_sp]
+
+        mrc     CP32(r11, HSR)                 /* Save exception syndrome */
+        str     r11, [sp, #UREGS_hsr]
+
+        mrs     r11, SPSR_hyp
+        str     r11, [sp, #UREGS_cpsr]
+        and     r11, #PSR_MODE_MASK
+        cmp     r11, #PSR_MODE_HYP
+        blne    save_guest_regs
+
+        /* We are ready to handle the trap, setup the registers and jump. */
         cpsie   \iflags
         adr     lr, return_from_trap
         mov     r0, sp

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