Interrupt code is shared between Book3E/S 64-bit systems for interrupt
handlers. Ensure that exit code correctly restores non-volatile gprs on
each system when CONFIG_INTERRUPT_SANITIZE_REGISTERS is enabled.

Also introduce macros for clearing/restoring registers on interrupt
entry for when this configuration option is either disabled or enabled.

Reviewed-by: Nicholas Piggin <npig...@gmail.com>
Signed-off-by: Rohan McLure <rmcl...@linux.ibm.com>
---
v4: New patch
---
 arch/powerpc/kernel/interrupt_64.S | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/powerpc/kernel/interrupt_64.S 
b/arch/powerpc/kernel/interrupt_64.S
index 978a173eb339..1ef4fdef74fb 100644
--- a/arch/powerpc/kernel/interrupt_64.S
+++ b/arch/powerpc/kernel/interrupt_64.S
@@ -408,9 +408,11 @@ interrupt_return_\srr\()_user: /* make backtraces match 
the _kernel variant */
 _ASM_NOKPROBE_SYMBOL(interrupt_return_\srr\()_user)
        addi    r3,r1,STACK_FRAME_OVERHEAD
        bl      interrupt_exit_user_prepare
+#ifndef CONFIG_INTERRUPT_SANITIZE_REGISTERS
        cmpdi   r3,0
        bne-    .Lrestore_nvgprs_\srr
 .Lrestore_nvgprs_\srr\()_cont:
+#endif
        std     r1,PACA_EXIT_SAVE_R1(r13) /* save r1 for restart */
 #ifdef CONFIG_PPC_BOOK3S
 .Linterrupt_return_\srr\()_user_rst_start:
@@ -424,6 +426,7 @@ _ASM_NOKPROBE_SYMBOL(interrupt_return_\srr\()_user)
        stb     r11,PACAIRQHAPPENED(r13) # clear out possible HARD_DIS
 
 .Lfast_user_interrupt_return_\srr\():
+       SANITIZE_RESTORE_NVGPRS()
 #ifdef CONFIG_PPC_BOOK3S
        .ifc \srr,srr
        lbz     r4,PACASRR_VALID(r13)
@@ -493,9 +496,11 @@ ALT_FTR_SECTION_END_IFCLR(CPU_FTR_STCX_CHECKS_ADDRESS)
        b       .       /* prevent speculative execution */
 .Linterrupt_return_\srr\()_user_rst_end:
 
+#ifndef CONFIG_INTERRUPT_SANITIZE_REGISTERS
 .Lrestore_nvgprs_\srr\():
        REST_NVGPRS(r1)
        b       .Lrestore_nvgprs_\srr\()_cont
+#endif
 
 #ifdef CONFIG_PPC_BOOK3S
 interrupt_return_\srr\()_user_restart:
@@ -576,6 +581,7 @@ _ASM_NOKPROBE_SYMBOL(interrupt_return_\srr\()_kernel)
        stb     r11,PACAIRQHAPPENED(r13) // clear the possible HARD_DIS
 
 .Lfast_kernel_interrupt_return_\srr\():
+       SANITIZE_RESTORE_NVGPRS()
        cmpdi   cr1,r3,0
 #ifdef CONFIG_PPC_BOOK3S
        .ifc \srr,srr
-- 
2.37.2

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