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bh=g5SIlfhNFVkGHqg4H9aglJHNTgTJdaH8G/qaojIJDnE=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=L6cdEA/BISwr7ZGYF7a704NDGC+im1GJ4f75VGUu82/h16AtX1OuAwGlV9RZIL3iN wTHwhWRwouSCgqYNm4ZyME8nNT67p8y462FT1X4IqDkxZcqIp22QV7Zj6C5AZrcJVC 0QT5qi2+96d67Gn0ORmwA+Bs/665rZSZ2l3fkU0M= From: Kevin Brodsky Date: Tue, 18 Aug 2026 15:08:50 +0100 Subject: [PATCH RFC v9 08/25] arm64: Initialize POR_EL1 register on cpu_resume() MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260818-kpkeys-v9-8-743ad31b2c8f@arm.com> References: <20260818-kpkeys-v9-0-743ad31b2c8f@arm.com> In-Reply-To: <20260818-kpkeys-v9-0-743ad31b2c8f@arm.com> To: linux-hardening@vger.kernel.org Cc: Kevin Brodsky , Andrew Morton , Andy Lutomirski , Catalin Marinas , Dave Hansen , "David Hildenbrand (Arm)" , Jann Horn , Jeff Xu , Joey Gouly , Kees Cook , Linu Cherian , Linus Walleij , Marc Zyngier , Mark Brown , Matthew Wilcox , Maxwell Bland , "Mike Rapoport (IBM)" , Peter Zijlstra , Pierre Langlois , =?utf-8?q?Pierre-Cl=C3=A9ment_Tosi?= , Quentin Perret , Rick Edgecombe , Ryan Roberts , Vlastimil Babka , Will Deacon , Yang Shi , Yeoreum Yun , linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, x86@kernel.org, Ira Weiny , Lorenzo Stoakes , Thomas Gleixner X-Mailer: b4 0.15.2 X-Developer-Signature: v=1; a=ed25519-sha256; t=1787062276; l=1238; i=kevin.brodsky@arm.com; s=20260427; h=from:subject:message-id; bh=X72DCdJX2SxlqX4hafcg68D9WxF9xj/CvQA2EQYYzDc=; b=JseJqSnqWF5VwY3b78AO3x1orBPCnLTkOtj4V+MVgokgLhHzhQg+2ITqTTwUd1hYOxGHqUo2+ WvBZb5/1pbMB6iiTfbLpaiRifOp3NpBGNVSiTnRWAfpIlMiCzYd4ZBz X-Developer-Key: i=kevin.brodsky@arm.com; a=ed25519; pk=N2QG+eJKrvkNovwhhwJhnJ4+ScVfsGCHldmqLfcMTFs= X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: C1C8A14000D X-Stat-Signature: fauebbtfnjofitqfkt7d3zjg4qe8q73e X-Rspam-User: X-HE-Tag: 1787062322-845346 X-HE-Meta: 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 qwiLgRlf bA/VPK4DimVhkC/6l8st7q6J+gaMPGJhOCuoX5TUvWB2+FnP3aXZwj+0WYChdE1o100+2J/ttK+GteWnCHJkJbfWxjcoecqiq7U6eNvMx6eevq25Al8vQP9YbuV4Rl+dXXAMjHyYjI4D4AjX9XKCY0RykxhPL64RuM1bPtZrZ+Kjg7xGG2VKrrfV3nueEoSWmwf6qKEXOgxmKmCyZMSkajNkfCVIkI8Z/VctupiZLMbDmRxquZgylUY2eTa50Hf/OPVkSyUxD0LF2kPxHa0gp2N4F9G5o3GJnpsReHfmVftOTvxbBJWCDTc/ydnwlbn0zw0dq9VMfddUNWBF1McLX0PGHEQ== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: From: Yeoreum Yun The POR_EL1 register is reset to an unknown value after cpu_suspend(). Since POR_EL1 always holds POR_EL1_INIT when entering cpu_suspend(), initialize POR_EL1 with POR_EL1_INIT before cpu_do_resume(). Signed-off-by: Yeoreum Yun Signed-off-by: Kevin Brodsky --- arch/arm64/kernel/sleep.S | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/arch/arm64/kernel/sleep.S b/arch/arm64/kernel/sleep.S index f093cdf71be1..e0a6ad85cd24 100644 --- a/arch/arm64/kernel/sleep.S +++ b/arch/arm64/kernel/sleep.S @@ -3,6 +3,7 @@ #include #include #include +#include #include .text @@ -134,6 +135,17 @@ SYM_FUNC_START(_cpu_resume) /* load sp from context */ ldr x2, [x0, #CPU_CTX_SP] mov sp, x2 + +#ifdef CONFIG_ARM64_POE +alternative_if_not ARM64_HAS_S1POE + b .Lskip_por_set +alternative_else_nop_endif + mov_q x2, POR_EL1_INIT + msr_s SYS_POR_EL1, x2 + /* isb can be skipped since cpu_do_resume() will do it. */ +.Lskip_por_set: +#endif /* CONFIG_ARM64_POE */ + /* * cpu_do_resume expects x0 to contain context address pointer */ -- 2.51.2