linux-kernel - [PATCH v2] ARM: pm: fix HYP/SVC mode mismatch when MCPM is used

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Message-id: <20190215105638.17476-1-m.szyprowski@samsung.com>
Date:   Fri, 15 Feb 2019 11:56:38 +0100
From:   Marek Szyprowski <m.szyprowski@...sung.com>
To:     linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Cc:     Marek Szyprowski <m.szyprowski@...sung.com>,
        Russell King <rmk+kernel@...linux.org.uk>,
        Nicolas Pitre <nicolas.pitre@...aro.org>,
        Kevin Hilman <khilman@...libre.com>,
        linux-samsung-soc@...r.kernel.org,
        Krzysztof Kozlowski <krzk@...nel.org>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
        Marian Mihailescu <mihailescu2m@...il.com>,
        Seung-Woo Kim <sw0312.kim@...sung.com>
Subject: [PATCH v2] ARM: pm: fix HYP/SVC mode mismatch when MCPM is used

MCPM does a soft reset of the CPUs and uses common cpu_resume() routine to
perform low-level platform initialization. This results in a try to install
HYP stubs for the second time for each CPU and results in false HYP/SVC
mode mismatch detection. The HYP stubs are already installed at the
beginning of the kernel initialization on the boot CPU (head.S) or in the
secondary_startup() for other CPUs. To fix this issue MCPM code should use
a cpu_resume() routine without HYP stubs installation.

This change fixes HYP/SVC mode mismatch on Samsung Exynos5422-based Odroid
XU3/XU4/HC1 boards.

Fixes: 3721924c8154 ("ARM: 8081/1: MCPM: provide infrastructure to allow for MCPM loopback")
Signed-off-by: Marek Szyprowski <m.szyprowski@...sung.com>
Acked-by: Nicolas Pitre <nico@...aro.org>
---
v2:
- fixed support for Thumb-mode kernel
---
 arch/arm/common/mcpm_entry.c   |  2 +-
 arch/arm/include/asm/suspend.h |  1 +
 arch/arm/kernel/sleep.S        | 12 ++++++++++++
 3 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/arch/arm/common/mcpm_entry.c b/arch/arm/common/mcpm_entry.c
index ad574d20415c..1b1b82b37ce0 100644
--- a/arch/arm/common/mcpm_entry.c
+++ b/arch/arm/common/mcpm_entry.c
@@ -381,7 +381,7 @@ static int __init nocache_trampoline(unsigned long _arg)
 	unsigned int cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1);
 	phys_reset_t phys_reset;
 
-	mcpm_set_entry_vector(cpu, cluster, cpu_resume);
+	mcpm_set_entry_vector(cpu, cluster, cpu_resume_no_hyp);
 	setup_mm_for_reboot();
 
 	__mcpm_cpu_going_down(cpu, cluster);
diff --git a/arch/arm/include/asm/suspend.h b/arch/arm/include/asm/suspend.h
index 452bbdcbcc83..506314265c6f 100644
--- a/arch/arm/include/asm/suspend.h
+++ b/arch/arm/include/asm/suspend.h
@@ -10,6 +10,7 @@ struct sleep_save_sp {
 };
 
 extern void cpu_resume(void);
+extern void cpu_resume_no_hyp(void);
 extern void cpu_resume_arm(void);
 extern int cpu_suspend(unsigned long, int (*)(unsigned long));
 
diff --git a/arch/arm/kernel/sleep.S b/arch/arm/kernel/sleep.S
index a8257fc9cf2a..5dc8b80bb693 100644
--- a/arch/arm/kernel/sleep.S
+++ b/arch/arm/kernel/sleep.S
@@ -120,6 +120,14 @@ ENDPROC(cpu_resume_after_mmu)
 	.text
 	.align
 
+#ifdef CONFIG_MCPM
+	.arm
+THUMB(	.thumb			)
+ENTRY(cpu_resume_no_hyp)
+ARM_BE8(setend be)			@ ensure we are in BE mode
+	b	no_hyp
+#endif
+
 #ifdef CONFIG_MMU
 	.arm
 ENTRY(cpu_resume_arm)
@@ -135,6 +143,7 @@ ARM_BE8(setend be)			@ ensure we are in BE mode
 	bl	__hyp_stub_install_secondary
 #endif
 	safe_svcmode_maskall r1
+no_hyp:
 	mov	r1, #0
 	ALT_SMP(mrc p15, 0, r0, c0, c0, 5)
 	ALT_UP_B(1f)
@@ -163,6 +172,9 @@ ENDPROC(cpu_resume)
 
 #ifdef CONFIG_MMU
 ENDPROC(cpu_resume_arm)
+#endif
+#ifdef CONFIG_MCPM
+ENDPROC(cpu_resume_no_hyp)
 #endif
 
 	.align 2
-- 
2.17.1