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From 9c0a3a7f4704d553aba657c23451885f0d0dc152 Mon Sep 17 00:00:00 2001 |
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From: Will Deacon <will.deacon@arm.com> |
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Date: Tue, 7 Aug 2018 13:43:06 +0100 |
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Subject: [PATCH 058/145] arm64: entry: Allow handling of undefined |
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instructions from EL1 |
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|
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[ Upstream commit 0bf0f444b2c49241b2b39aa3cf210d7c95ef6c34 ] |
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|
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Rather than panic() when taking an undefined instruction exception from |
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EL1, allow a hook to be registered in case we want to emulate the |
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instruction, like we will for the SSBS PSTATE manipulation instructions. |
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|
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Signed-off-by: Will Deacon <will.deacon@arm.com> |
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Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> |
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Signed-off-by: Sasha Levin <sashal@kernel.org> |
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--- |
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arch/arm64/kernel/entry.S | 2 +- |
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arch/arm64/kernel/traps.c | 11 +++++++---- |
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2 files changed, 8 insertions(+), 5 deletions(-) |
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|
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diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S |
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index 09dbea221a27..8556876c9109 100644 |
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--- a/arch/arm64/kernel/entry.S |
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+++ b/arch/arm64/kernel/entry.S |
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@@ -589,7 +589,7 @@ el1_undef: |
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inherit_daif pstate=x23, tmp=x2 |
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mov x0, sp |
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bl do_undefinstr |
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- ASM_BUG() |
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+ kernel_exit 1 |
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el1_dbg: |
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/* |
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* Debug exception handling |
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diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c |
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index 039e9ff379cc..b9da093e0341 100644 |
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--- a/arch/arm64/kernel/traps.c |
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+++ b/arch/arm64/kernel/traps.c |
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@@ -310,10 +310,12 @@ static int call_undef_hook(struct pt_regs *regs) |
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int (*fn)(struct pt_regs *regs, u32 instr) = NULL; |
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void __user *pc = (void __user *)instruction_pointer(regs); |
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|
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- if (!user_mode(regs)) |
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- return 1; |
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- |
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- if (compat_thumb_mode(regs)) { |
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+ if (!user_mode(regs)) { |
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+ __le32 instr_le; |
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+ if (probe_kernel_address((__force __le32 *)pc, instr_le)) |
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+ goto exit; |
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+ instr = le32_to_cpu(instr_le); |
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+ } else if (compat_thumb_mode(regs)) { |
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/* 16-bit Thumb instruction */ |
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__le16 instr_le; |
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if (get_user(instr_le, (__le16 __user *)pc)) |
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@@ -407,6 +409,7 @@ asmlinkage void __exception do_undefinstr(struct pt_regs *regs) |
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return; |
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|
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force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc); |
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+ BUG_ON(!user_mode(regs)); |
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} |
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|
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void cpu_enable_cache_maint_trap(const struct arm64_cpu_capabilities *__unused) |
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-- |
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2.19.1 |
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