arm64: Fix cleared E0POE bit after cpu_suspend()/resume()

TCR2_ELx.E0POE is set during smp_init().
However, this bit is not reprogrammed when the CPU enters suspension and
later resumes via cpu_resume(), as __cpu_setup() does not re-enable E0POE
and there is no save/restore logic for the TCR2_ELx system register.

As a result, the E0POE feature no longer works after cpu_resume().

To address this, save and restore TCR2_EL1 in the cpu_suspend()/cpu_resume()
path, rather than adding related logic to __cpu_setup(), taking into account
possible future extensions of the TCR2_ELx feature.

Fixes: bf83dae90fbc ("arm64: enable the Permission Overlay Extension for EL0")
Cc: <stable@vger.kernel.org> # 6.12.x
Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Kevin Brodsky <kevin.brodsky@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/arch/arm64/include/asm/suspend.h b/arch/arm64/include/asm/suspend.h
index e65f33edf9d61d025d33d20fb77f3297ebd35bda..e9ce68d50ba45131a147f19dc9c19212c22b02ce 100644 (file)
--- a/arch/arm64/include/asm/suspend.h
+++ b/arch/arm64/include/asm/suspend.h
@@ -2,7 +2,7 @@
 #ifndef __ASM_SUSPEND_H
 #define __ASM_SUSPEND_H
 
-#define NR_CTX_REGS 13
+#define NR_CTX_REGS 14
 #define NR_CALLEE_SAVED_REGS 12
 
 /*

diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S
index 01e868116448886d5c3c8dcd89687bc5df005fcb..5d907ce3b6d3f0c26b9aeddae5ce354d935e8393 100644 (file)
--- a/arch/arm64/mm/proc.S
+++ b/arch/arm64/mm/proc.S
@@ -110,6 +110,10 @@ SYM_FUNC_START(cpu_do_suspend)
         * call stack.
         */
        str     x18, [x0, #96]
+alternative_if ARM64_HAS_TCR2
+       mrs     x2, REG_TCR2_EL1
+       str     x2, [x0, #104]
+alternative_else_nop_endif
        ret
 SYM_FUNC_END(cpu_do_suspend)
 
@@ -144,6 +148,10 @@ SYM_FUNC_START(cpu_do_resume)
        msr     tcr_el1, x8
        msr     vbar_el1, x9
        msr     mdscr_el1, x10
+alternative_if ARM64_HAS_TCR2
+       ldr     x2, [x0, #104]
+       msr     REG_TCR2_EL1, x2
+alternative_else_nop_endif
 
        msr     sctlr_el1, x12
        set_this_cpu_offset x13