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Diffstat (limited to 'common/recipes-kernel/linux/linux-yocto-4.9.21/0019-x86-retpoline-Simplify-vmexit_fill_RSB.patch')
-rw-r--r--common/recipes-kernel/linux/linux-yocto-4.9.21/0019-x86-retpoline-Simplify-vmexit_fill_RSB.patch261
1 files changed, 0 insertions, 261 deletions
diff --git a/common/recipes-kernel/linux/linux-yocto-4.9.21/0019-x86-retpoline-Simplify-vmexit_fill_RSB.patch b/common/recipes-kernel/linux/linux-yocto-4.9.21/0019-x86-retpoline-Simplify-vmexit_fill_RSB.patch
deleted file mode 100644
index 60269d5c..00000000
--- a/common/recipes-kernel/linux/linux-yocto-4.9.21/0019-x86-retpoline-Simplify-vmexit_fill_RSB.patch
+++ /dev/null
@@ -1,261 +0,0 @@
-From 53b3bd3747acd3d6633feaa63a998f854d90551c Mon Sep 17 00:00:00 2001
-From: Borislav Petkov <bp@alien8.de>
-Date: Sat, 27 Jan 2018 16:24:33 +0000
-Subject: [PATCH 19/42] x86/retpoline: Simplify vmexit_fill_RSB()
-
-(cherry picked from commit 1dde7415e99933bb7293d6b2843752cbdb43ec11)
-
-Simplify it to call an asm-function instead of pasting 41 insn bytes at
-every call site. Also, add alignment to the macro as suggested here:
-
- https://support.google.com/faqs/answer/7625886
-
-[dwmw2: Clean up comments, let it clobber %ebx and just tell the compiler]
-
-Signed-off-by: Borislav Petkov <bp@suse.de>
-Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
-Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
-Cc: ak@linux.intel.com
-Cc: dave.hansen@intel.com
-Cc: karahmed@amazon.de
-Cc: arjan@linux.intel.com
-Cc: torvalds@linux-foundation.org
-Cc: peterz@infradead.org
-Cc: bp@alien8.de
-Cc: pbonzini@redhat.com
-Cc: tim.c.chen@linux.intel.com
-Cc: gregkh@linux-foundation.org
-Link: https://lkml.kernel.org/r/1517070274-12128-3-git-send-email-dwmw@amazon.co.uk
-Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
-Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
----
- arch/x86/entry/entry_32.S | 3 +-
- arch/x86/entry/entry_64.S | 3 +-
- arch/x86/include/asm/asm-prototypes.h | 3 ++
- arch/x86/include/asm/nospec-branch.h | 70 ++++-------------------------------
- arch/x86/lib/Makefile | 1 +
- arch/x86/lib/retpoline.S | 56 ++++++++++++++++++++++++++++
- 6 files changed, 71 insertions(+), 65 deletions(-)
-
-diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S
-index a76dc73..f5434b4 100644
---- a/arch/x86/entry/entry_32.S
-+++ b/arch/x86/entry/entry_32.S
-@@ -237,7 +237,8 @@ ENTRY(__switch_to_asm)
- * exist, overwrite the RSB with entries which capture
- * speculative execution to prevent attack.
- */
-- FILL_RETURN_BUFFER %ebx, RSB_CLEAR_LOOPS, X86_FEATURE_RSB_CTXSW
-+ /* Clobbers %ebx */
-+ FILL_RETURN_BUFFER RSB_CLEAR_LOOPS, X86_FEATURE_RSB_CTXSW
- #endif
-
- /* restore callee-saved registers */
-diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
-index 16146eb..e422e15 100644
---- a/arch/x86/entry/entry_64.S
-+++ b/arch/x86/entry/entry_64.S
-@@ -435,7 +435,8 @@ ENTRY(__switch_to_asm)
- * exist, overwrite the RSB with entries which capture
- * speculative execution to prevent attack.
- */
-- FILL_RETURN_BUFFER %r12, RSB_CLEAR_LOOPS, X86_FEATURE_RSB_CTXSW
-+ /* Clobbers %rbx */
-+ FILL_RETURN_BUFFER RSB_CLEAR_LOOPS, X86_FEATURE_RSB_CTXSW
- #endif
-
- /* restore callee-saved registers */
-diff --git a/arch/x86/include/asm/asm-prototypes.h b/arch/x86/include/asm/asm-prototypes.h
-index 5a25ada..1666542 100644
---- a/arch/x86/include/asm/asm-prototypes.h
-+++ b/arch/x86/include/asm/asm-prototypes.h
-@@ -37,4 +37,7 @@ INDIRECT_THUNK(dx)
- INDIRECT_THUNK(si)
- INDIRECT_THUNK(di)
- INDIRECT_THUNK(bp)
-+asmlinkage void __fill_rsb(void);
-+asmlinkage void __clear_rsb(void);
-+
- #endif /* CONFIG_RETPOLINE */
-diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h
-index 19ecb54..df4ecec 100644
---- a/arch/x86/include/asm/nospec-branch.h
-+++ b/arch/x86/include/asm/nospec-branch.h
-@@ -7,50 +7,6 @@
- #include <asm/alternative-asm.h>
- #include <asm/cpufeatures.h>
-
--/*
-- * Fill the CPU return stack buffer.
-- *
-- * Each entry in the RSB, if used for a speculative 'ret', contains an
-- * infinite 'pause; lfence; jmp' loop to capture speculative execution.
-- *
-- * This is required in various cases for retpoline and IBRS-based
-- * mitigations for the Spectre variant 2 vulnerability. Sometimes to
-- * eliminate potentially bogus entries from the RSB, and sometimes
-- * purely to ensure that it doesn't get empty, which on some CPUs would
-- * allow predictions from other (unwanted!) sources to be used.
-- *
-- * We define a CPP macro such that it can be used from both .S files and
-- * inline assembly. It's possible to do a .macro and then include that
-- * from C via asm(".include <asm/nospec-branch.h>") but let's not go there.
-- */
--
--#define RSB_CLEAR_LOOPS 32 /* To forcibly overwrite all entries */
--#define RSB_FILL_LOOPS 16 /* To avoid underflow */
--
--/*
-- * Google experimented with loop-unrolling and this turned out to be
-- * the optimal version — two calls, each with their own speculation
-- * trap should their return address end up getting used, in a loop.
-- */
--#define __FILL_RETURN_BUFFER(reg, nr, sp) \
-- mov $(nr/2), reg; \
--771: \
-- call 772f; \
--773: /* speculation trap */ \
-- pause; \
-- lfence; \
-- jmp 773b; \
--772: \
-- call 774f; \
--775: /* speculation trap */ \
-- pause; \
-- lfence; \
-- jmp 775b; \
--774: \
-- dec reg; \
-- jnz 771b; \
-- add $(BITS_PER_LONG/8) * nr, sp;
--
- #ifdef __ASSEMBLY__
-
- /*
-@@ -121,17 +77,10 @@
- #endif
- .endm
-
-- /*
-- * A simpler FILL_RETURN_BUFFER macro. Don't make people use the CPP
-- * monstrosity above, manually.
-- */
--.macro FILL_RETURN_BUFFER reg:req nr:req ftr:req
-+/* This clobbers the BX register */
-+.macro FILL_RETURN_BUFFER nr:req ftr:req
- #ifdef CONFIG_RETPOLINE
-- ANNOTATE_NOSPEC_ALTERNATIVE
-- ALTERNATIVE "jmp .Lskip_rsb_\@", \
-- __stringify(__FILL_RETURN_BUFFER(\reg,\nr,%_ASM_SP)) \
-- \ftr
--.Lskip_rsb_\@:
-+ ALTERNATIVE "", "call __clear_rsb", \ftr
- #endif
- .endm
-
-@@ -206,15 +155,10 @@ extern char __indirect_thunk_end[];
- static inline void vmexit_fill_RSB(void)
- {
- #ifdef CONFIG_RETPOLINE
-- unsigned long loops;
--
-- asm volatile (ANNOTATE_NOSPEC_ALTERNATIVE
-- ALTERNATIVE("jmp 910f",
-- __stringify(__FILL_RETURN_BUFFER(%0, RSB_CLEAR_LOOPS, %1)),
-- X86_FEATURE_RETPOLINE)
-- "910:"
-- : "=r" (loops), ASM_CALL_CONSTRAINT
-- : : "memory" );
-+ alternative_input("",
-+ "call __fill_rsb",
-+ X86_FEATURE_RETPOLINE,
-+ ASM_NO_INPUT_CLOBBER(_ASM_BX, "memory"));
- #endif
- }
-
-diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile
-index 6bf1898..4ad7c4d 100644
---- a/arch/x86/lib/Makefile
-+++ b/arch/x86/lib/Makefile
-@@ -26,6 +26,7 @@ lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem.o
- lib-$(CONFIG_INSTRUCTION_DECODER) += insn.o inat.o
- lib-$(CONFIG_RANDOMIZE_BASE) += kaslr.o
- lib-$(CONFIG_RETPOLINE) += retpoline.o
-+OBJECT_FILES_NON_STANDARD_retpoline.o :=y
-
- obj-y += msr.o msr-reg.o msr-reg-export.o hweight.o
-
-diff --git a/arch/x86/lib/retpoline.S b/arch/x86/lib/retpoline.S
-index c909961..480edc3 100644
---- a/arch/x86/lib/retpoline.S
-+++ b/arch/x86/lib/retpoline.S
-@@ -7,6 +7,7 @@
- #include <asm/alternative-asm.h>
- #include <asm/export.h>
- #include <asm/nospec-branch.h>
-+#include <asm/bitsperlong.h>
-
- .macro THUNK reg
- .section .text.__x86.indirect_thunk
-@@ -46,3 +47,58 @@ GENERATE_THUNK(r13)
- GENERATE_THUNK(r14)
- GENERATE_THUNK(r15)
- #endif
-+
-+/*
-+ * Fill the CPU return stack buffer.
-+ *
-+ * Each entry in the RSB, if used for a speculative 'ret', contains an
-+ * infinite 'pause; lfence; jmp' loop to capture speculative execution.
-+ *
-+ * This is required in various cases for retpoline and IBRS-based
-+ * mitigations for the Spectre variant 2 vulnerability. Sometimes to
-+ * eliminate potentially bogus entries from the RSB, and sometimes
-+ * purely to ensure that it doesn't get empty, which on some CPUs would
-+ * allow predictions from other (unwanted!) sources to be used.
-+ *
-+ * Google experimented with loop-unrolling and this turned out to be
-+ * the optimal version - two calls, each with their own speculation
-+ * trap should their return address end up getting used, in a loop.
-+ */
-+.macro STUFF_RSB nr:req sp:req
-+ mov $(\nr / 2), %_ASM_BX
-+ .align 16
-+771:
-+ call 772f
-+773: /* speculation trap */
-+ pause
-+ lfence
-+ jmp 773b
-+ .align 16
-+772:
-+ call 774f
-+775: /* speculation trap */
-+ pause
-+ lfence
-+ jmp 775b
-+ .align 16
-+774:
-+ dec %_ASM_BX
-+ jnz 771b
-+ add $((BITS_PER_LONG/8) * \nr), \sp
-+.endm
-+
-+#define RSB_FILL_LOOPS 16 /* To avoid underflow */
-+
-+ENTRY(__fill_rsb)
-+ STUFF_RSB RSB_FILL_LOOPS, %_ASM_SP
-+ ret
-+END(__fill_rsb)
-+EXPORT_SYMBOL_GPL(__fill_rsb)
-+
-+#define RSB_CLEAR_LOOPS 32 /* To forcibly overwrite all entries */
-+
-+ENTRY(__clear_rsb)
-+ STUFF_RSB RSB_CLEAR_LOOPS, %_ASM_SP
-+ ret
-+END(__clear_rsb)
-+EXPORT_SYMBOL_GPL(__clear_rsb)
---
-2.7.4
-
generated by cgit 1.2.3-korg (git 2.39.0) at 2024-04-26 23:31:09 +0000