linux-kernel - [PATCH AUTOSEL 6.1 13/17] arm64: set POR

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Message-ID: <20241023143202.2981992-13-sashal@kernel.org>
Date: Wed, 23 Oct 2024 10:31:52 -0400
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org,
	stable@...r.kernel.org
Cc: Joey Gouly <joey.gouly@....com>,
	Will Deacon <will@...nel.org>,
	Catalin Marinas <catalin.marinas@....com>,
	Kevin Brodsky <Kevin.Brodsky@....com>,
	Sasha Levin <sashal@...nel.org>,
	pcc@...gle.com,
	dawei.li@...ngroup.cn,
	linux-arm-kernel@...ts.infradead.org
Subject: [PATCH AUTOSEL 6.1 13/17] arm64: set POR_EL0 for kernel threads

From: Joey Gouly <joey.gouly@....com>

[ Upstream commit e3e85271330b18f487ab3032ea9ca0601efeafaf ]

Restrict kernel threads to only have RWX overlays for pkey 0.  This matches
what arch/x86 does, by defaulting to a restrictive PKRU.

Signed-off-by: Joey Gouly <joey.gouly@....com>
Cc: Will Deacon <will@...nel.org>
Cc: Catalin Marinas <catalin.marinas@....com>
Reviewed-by: Kevin Brodsky <Kevin.Brodsky@....com>
Link: https://lore.kernel.org/r/20241001133618.1547996-2-joey.gouly@arm.com
Signed-off-by: Will Deacon <will@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 arch/arm64/kernel/process.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index 044a7d7f1f6ad..048fe09da8a07 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -399,6 +399,9 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
 
 		p->thread.cpu_context.x19 = (unsigned long)args->fn;
 		p->thread.cpu_context.x20 = (unsigned long)args->fn_arg;
+
+		if (system_supports_poe())
+			p->thread.por_el0 = POR_EL0_INIT;
 	}
 	p->thread.cpu_context.pc = (unsigned long)ret_from_fork;
 	p->thread.cpu_context.sp = (unsigned long)childregs;
-- 
2.43.0