0570f90d28
This allows us to fix the ZFS SIMD patch for 5.0 kernel way easier. Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
104 lines
3.4 KiB
Diff
104 lines
3.4 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Thomas Lamprecht <t.lamprecht@proxmox.com>
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Date: Wed, 3 Apr 2019 18:41:50 +0200
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Subject: [PATCH] x86/fpu: backport copy_kernel_to_XYZ_err helpers
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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partial cherry-pick from upstream 5.2 "86/fpu: Restore from kernel
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memory on the 64-bit path too"
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commit 926b21f37b072ae4c117052de45a975c6d468fec
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Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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Namely, only backport the added helpers, none of the semantic changes.
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relevant parts of the original commit message:
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> In order to avoid that mess, copy the FPU state from userland, validate
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> it and then load it. The copy_kernel_…() helpers are basically just
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> like the old helpers except that they operate on kernel memory and the
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> fault handler just sets the error value and the caller handles it.
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Link: https://lkml.kernel.org/r/20190403164156.19645-22-bigeasy@linutronix.de
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(partial cherry picked from commit 926b21f37b072ae4c117052de45a975c6d468fec)
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Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
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---
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arch/x86/include/asm/fpu/internal.h | 43 +++++++++++++++++++++++++++++
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1 file changed, 43 insertions(+)
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diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h
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index fa2c93cb42a2..f3193ab0a2fb 100644
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--- a/arch/x86/include/asm/fpu/internal.h
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+++ b/arch/x86/include/asm/fpu/internal.h
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@@ -122,6 +122,21 @@ extern void fpstate_sanitize_xstate(struct fpu *fpu);
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err; \
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})
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+#define kernel_insn_err(insn, output, input...) \
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+({ \
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+ int err; \
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+ asm volatile("1:" #insn "\n\t" \
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+ "2:\n" \
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+ ".section .fixup,\"ax\"\n" \
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+ "3: movl $-1,%[err]\n" \
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+ " jmp 2b\n" \
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+ ".previous\n" \
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+ _ASM_EXTABLE(1b, 3b) \
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+ : [err] "=r" (err), output \
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+ : "0"(0), input); \
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+ err; \
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+})
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+
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#define kernel_insn(insn, output, input...) \
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asm volatile("1:" #insn "\n\t" \
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"2:\n" \
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@@ -158,6 +173,14 @@ static inline void copy_kernel_to_fxregs(struct fxregs_state *fx)
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}
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}
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+static inline int copy_kernel_to_fxregs_err(struct fxregs_state *fx)
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+{
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+ if (IS_ENABLED(CONFIG_X86_32))
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+ return kernel_insn_err(fxrstor %[fx], "=m" (*fx), [fx] "m" (*fx));
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+ else
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+ return kernel_insn_err(fxrstorq %[fx], "=m" (*fx), [fx] "m" (*fx));
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+}
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+
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static inline int copy_user_to_fxregs(struct fxregs_state __user *fx)
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{
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if (IS_ENABLED(CONFIG_X86_32))
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@@ -175,6 +198,11 @@ static inline void copy_kernel_to_fregs(struct fregs_state *fx)
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kernel_insn(frstor %[fx], "=m" (*fx), [fx] "m" (*fx));
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}
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+static inline int copy_kernel_to_fregs_err(struct fregs_state *fx)
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+{
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+ return kernel_insn_err(frstor %[fx], "=m" (*fx), [fx] "m" (*fx));
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+}
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+
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static inline int copy_user_to_fregs(struct fregs_state __user *fx)
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{
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return user_insn(frstor %[fx], "=m" (*fx), [fx] "m" (*fx));
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@@ -400,6 +428,21 @@ static inline int copy_user_to_xregs(struct xregs_state __user *buf, u64 mask)
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return err;
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}
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+/*
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+ * Restore xstate from kernel space xsave area, return an error code instead of
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+ * an exception.
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+ */
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+static inline int copy_kernel_to_xregs_err(struct xregs_state *xstate, u64 mask)
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+{
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+ u32 lmask = mask;
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+ u32 hmask = mask >> 32;
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+ int err;
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+
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+ XSTATE_OP(XRSTOR, xstate, lmask, hmask, err);
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+
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+ return err;
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+}
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+
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/*
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* These must be called with preempt disabled. Returns
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* 'true' if the FPU state is still intact and we can
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