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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, Edward Tran <edward.tran@oracle.com>,
	Awais Tanveer <awais.tanveer@oracle.com>,
	Ankur Arora <ankur.a.arora@oracle.com>,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	Alexandre Chartre <alexandre.chartre@oracle.com>,
	Borislav Petkov <bp@suse.de>,
	Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Subject: [PATCH 5.15 76/89] x86/kexec: Disable RET on kexec
Date: Fri, 22 Jul 2022 11:11:50 +0200	[thread overview]
Message-ID: <20220722091137.595809346@linuxfoundation.org> (raw)
In-Reply-To: <20220722091133.320803732@linuxfoundation.org>

From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

commit 697977d8415d61f3acbc4ee6d564c9dcf0309507 upstream.

All the invocations unroll to __x86_return_thunk and this file
must be PIC independent.

This fixes kexec on 64-bit AMD boxes.

  [ bp: Fix 32-bit build. ]

Reported-by: Edward Tran <edward.tran@oracle.com>
Reported-by: Awais Tanveer <awais.tanveer@oracle.com>
Suggested-by: Ankur Arora <ankur.a.arora@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/x86/kernel/relocate_kernel_32.S |   25 +++++++++++++++++++------
 arch/x86/kernel/relocate_kernel_64.S |   23 +++++++++++++++++------
 2 files changed, 36 insertions(+), 12 deletions(-)

--- a/arch/x86/kernel/relocate_kernel_32.S
+++ b/arch/x86/kernel/relocate_kernel_32.S
@@ -7,10 +7,12 @@
 #include <linux/linkage.h>
 #include <asm/page_types.h>
 #include <asm/kexec.h>
+#include <asm/nospec-branch.h>
 #include <asm/processor-flags.h>
 
 /*
- * Must be relocatable PIC code callable as a C function
+ * Must be relocatable PIC code callable as a C function, in particular
+ * there must be a plain RET and not jump to return thunk.
  */
 
 #define PTR(x) (x << 2)
@@ -91,7 +93,9 @@ SYM_CODE_START_NOALIGN(relocate_kernel)
 	movl    %edi, %eax
 	addl    $(identity_mapped - relocate_kernel), %eax
 	pushl   %eax
-	RET
+	ANNOTATE_UNRET_SAFE
+	ret
+	int3
 SYM_CODE_END(relocate_kernel)
 
 SYM_CODE_START_LOCAL_NOALIGN(identity_mapped)
@@ -159,12 +163,15 @@ SYM_CODE_START_LOCAL_NOALIGN(identity_ma
 	xorl    %edx, %edx
 	xorl    %esi, %esi
 	xorl    %ebp, %ebp
-	RET
+	ANNOTATE_UNRET_SAFE
+	ret
+	int3
 1:
 	popl	%edx
 	movl	CP_PA_SWAP_PAGE(%edi), %esp
 	addl	$PAGE_SIZE, %esp
 2:
+	ANNOTATE_RETPOLINE_SAFE
 	call	*%edx
 
 	/* get the re-entry point of the peer system */
@@ -190,7 +197,9 @@ SYM_CODE_START_LOCAL_NOALIGN(identity_ma
 	movl	%edi, %eax
 	addl	$(virtual_mapped - relocate_kernel), %eax
 	pushl	%eax
-	RET
+	ANNOTATE_UNRET_SAFE
+	ret
+	int3
 SYM_CODE_END(identity_mapped)
 
 SYM_CODE_START_LOCAL_NOALIGN(virtual_mapped)
@@ -208,7 +217,9 @@ SYM_CODE_START_LOCAL_NOALIGN(virtual_map
 	popl	%edi
 	popl	%esi
 	popl	%ebx
-	RET
+	ANNOTATE_UNRET_SAFE
+	ret
+	int3
 SYM_CODE_END(virtual_mapped)
 
 	/* Do the copies */
@@ -271,7 +282,9 @@ SYM_CODE_START_LOCAL_NOALIGN(swap_pages)
 	popl	%edi
 	popl	%ebx
 	popl	%ebp
-	RET
+	ANNOTATE_UNRET_SAFE
+	ret
+	int3
 SYM_CODE_END(swap_pages)
 
 	.globl kexec_control_code_size
--- a/arch/x86/kernel/relocate_kernel_64.S
+++ b/arch/x86/kernel/relocate_kernel_64.S
@@ -13,7 +13,8 @@
 #include <asm/unwind_hints.h>
 
 /*
- * Must be relocatable PIC code callable as a C function
+ * Must be relocatable PIC code callable as a C function, in particular
+ * there must be a plain RET and not jump to return thunk.
  */
 
 #define PTR(x) (x << 3)
@@ -104,7 +105,9 @@ SYM_CODE_START_NOALIGN(relocate_kernel)
 	/* jump to identity mapped page */
 	addq	$(identity_mapped - relocate_kernel), %r8
 	pushq	%r8
-	RET
+	ANNOTATE_UNRET_SAFE
+	ret
+	int3
 SYM_CODE_END(relocate_kernel)
 
 SYM_CODE_START_LOCAL_NOALIGN(identity_mapped)
@@ -191,7 +194,9 @@ SYM_CODE_START_LOCAL_NOALIGN(identity_ma
 	xorl	%r14d, %r14d
 	xorl	%r15d, %r15d
 
-	RET
+	ANNOTATE_UNRET_SAFE
+	ret
+	int3
 
 1:
 	popq	%rdx
@@ -210,7 +215,9 @@ SYM_CODE_START_LOCAL_NOALIGN(identity_ma
 	call	swap_pages
 	movq	$virtual_mapped, %rax
 	pushq	%rax
-	RET
+	ANNOTATE_UNRET_SAFE
+	ret
+	int3
 SYM_CODE_END(identity_mapped)
 
 SYM_CODE_START_LOCAL_NOALIGN(virtual_mapped)
@@ -231,7 +238,9 @@ SYM_CODE_START_LOCAL_NOALIGN(virtual_map
 	popq	%r12
 	popq	%rbp
 	popq	%rbx
-	RET
+	ANNOTATE_UNRET_SAFE
+	ret
+	int3
 SYM_CODE_END(virtual_mapped)
 
 	/* Do the copies */
@@ -288,7 +297,9 @@ SYM_CODE_START_LOCAL_NOALIGN(swap_pages)
 	lea	PAGE_SIZE(%rax), %rsi
 	jmp	0b
 3:
-	RET
+	ANNOTATE_UNRET_SAFE
+	ret
+	int3
 SYM_CODE_END(swap_pages)
 
 	.globl kexec_control_code_size



  parent reply	other threads:[~2022-07-22  9:26 UTC|newest]

Thread overview: 96+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-22  9:10 [PATCH 5.15 00/89] 5.15.57-rc1 review Greg Kroah-Hartman
2022-07-22  9:10 ` [PATCH 5.15 01/89] x86/traps: Use pt_regs directly in fixup_bad_iret() Greg Kroah-Hartman
2022-07-22  9:10 ` [PATCH 5.15 02/89] x86/entry: Switch the stack after error_entry() returns Greg Kroah-Hartman
2022-07-22  9:10 ` [PATCH 5.15 03/89] x86/entry: Move PUSH_AND_CLEAR_REGS out of error_entry() Greg Kroah-Hartman
2022-07-22  9:10 ` [PATCH 5.15 04/89] x86/entry: Dont call error_entry() for XENPV Greg Kroah-Hartman
2022-07-22  9:10 ` [PATCH 5.15 05/89] objtool: Classify symbols Greg Kroah-Hartman
2022-07-22  9:10 ` [PATCH 5.15 06/89] objtool: Explicitly avoid self modifying code in .altinstr_replacement Greg Kroah-Hartman
2022-07-22  9:10 ` [PATCH 5.15 07/89] objtool: Shrink struct instruction Greg Kroah-Hartman
2022-07-22  9:10 ` [PATCH 5.15 08/89] objtool,x86: Replace alternatives with .retpoline_sites Greg Kroah-Hartman
2022-07-22  9:10 ` [PATCH 5.15 09/89] objtool: Introduce CFI hash Greg Kroah-Hartman
2022-07-22  9:10 ` [PATCH 5.15 10/89] x86/retpoline: Remove unused replacement symbols Greg Kroah-Hartman
2022-07-22  9:10 ` [PATCH 5.15 11/89] x86/asm: Fix register order Greg Kroah-Hartman
2022-07-22  9:10 ` [PATCH 5.15 12/89] x86/asm: Fixup odd GEN-for-each-reg.h usage Greg Kroah-Hartman
2022-07-22  9:10 ` [PATCH 5.15 13/89] x86/retpoline: Move the retpoline thunk declarations to nospec-branch.h Greg Kroah-Hartman
2022-07-22  9:10 ` [PATCH 5.15 14/89] x86/retpoline: Create a retpoline thunk array Greg Kroah-Hartman
2022-07-22  9:10 ` [PATCH 5.15 15/89] x86/alternative: Implement .retpoline_sites support Greg Kroah-Hartman
2022-07-22  9:10 ` [PATCH 5.15 16/89] x86/alternative: Handle Jcc __x86_indirect_thunk_\reg Greg Kroah-Hartman
2022-07-22  9:10 ` [PATCH 5.15 17/89] x86/alternative: Try inline spectre_v2=retpoline,amd Greg Kroah-Hartman
2022-07-22  9:10 ` [PATCH 5.15 18/89] x86/alternative: Add debug prints to apply_retpolines() Greg Kroah-Hartman
2022-07-22  9:10 ` [PATCH 5.15 19/89] bpf,x86: Simplify computing label offsets Greg Kroah-Hartman
2022-07-22  9:10 ` [PATCH 5.15 20/89] bpf,x86: Respect X86_FEATURE_RETPOLINE* Greg Kroah-Hartman
2022-07-22  9:10 ` [PATCH 5.15 21/89] objtool: Default ignore INT3 for unreachable Greg Kroah-Hartman
2022-07-22  9:10 ` [PATCH 5.15 22/89] x86/entry: Remove skip_r11rcx Greg Kroah-Hartman
2022-07-22  9:10 ` [PATCH 5.15 23/89] x86/realmode: build with -D__DISABLE_EXPORTS Greg Kroah-Hartman
2022-07-22  9:10 ` [PATCH 5.15 24/89] x86/kvm/vmx: Make noinstr clean Greg Kroah-Hartman
2022-07-22  9:10 ` [PATCH 5.15 25/89] x86/cpufeatures: Move RETPOLINE flags to word 11 Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 26/89] x86/retpoline: Cleanup some #ifdefery Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 27/89] x86/retpoline: Swizzle retpoline thunk Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 28/89] x86/retpoline: Use -mfunction-return Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 29/89] x86: Undo return-thunk damage Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 30/89] x86,objtool: Create .return_sites Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 31/89] objtool: skip non-text sections when adding return-thunk sites Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 32/89] x86,static_call: Use alternative RET encoding Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 33/89] x86/ftrace: " Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 34/89] x86/bpf: " Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 35/89] x86/kvm: Fix SETcc emulation for return thunks Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 36/89] x86/vsyscall_emu/64: Dont use RET in vsyscall emulation Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 37/89] x86/sev: Avoid using __x86_return_thunk Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 38/89] x86: Use return-thunk in asm code Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 39/89] x86/entry: Avoid very early RET Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 40/89] objtool: Treat .text.__x86.* as noinstr Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 41/89] x86: Add magic AMD return-thunk Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 42/89] x86/bugs: Report AMD retbleed vulnerability Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 43/89] x86/bugs: Add AMD retbleed= boot parameter Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 44/89] x86/bugs: Enable STIBP for JMP2RET Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 45/89] x86/bugs: Keep a per-CPU IA32_SPEC_CTRL value Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 46/89] x86/entry: Add kernel IBRS implementation Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 47/89] x86/bugs: Optimize SPEC_CTRL MSR writes Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 48/89] x86/speculation: Add spectre_v2=ibrs option to support Kernel IBRS Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 49/89] x86/bugs: Split spectre_v2_select_mitigation() and spectre_v2_user_select_mitigation() Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 50/89] x86/bugs: Report Intel retbleed vulnerability Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 51/89] intel_idle: Disable IBRS during long idle Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 52/89] objtool: Update Retpoline validation Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 53/89] x86/xen: Rename SYS* entry points Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 54/89] x86/xen: Add UNTRAIN_RET Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 55/89] x86/bugs: Add retbleed=ibpb Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 56/89] x86/bugs: Do IBPB fallback check only once Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 57/89] objtool: Add entry UNRET validation Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 58/89] x86/cpu/amd: Add Spectral Chicken Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 59/89] x86/speculation: Fix RSB filling with CONFIG_RETPOLINE=n Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 60/89] x86/speculation: Fix firmware entry SPEC_CTRL handling Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 61/89] x86/speculation: Fix SPEC_CTRL write on SMT state change Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 62/89] x86/speculation: Use cached host SPEC_CTRL value for guest entry/exit Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 63/89] x86/speculation: Remove x86_spec_ctrl_mask Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 64/89] objtool: Re-add UNWIND_HINT_{SAVE_RESTORE} Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 65/89] KVM: VMX: Flatten __vmx_vcpu_run() Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 66/89] KVM: VMX: Convert launched argument to flags Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 67/89] KVM: VMX: Prevent guest RSB poisoning attacks with eIBRS Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 68/89] KVM: VMX: Fix IBRS handling after vmexit Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 69/89] x86/speculation: Fill RSB on vmexit for IBRS Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 70/89] x86/common: Stamp out the stepping madness Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 71/89] x86/cpu/amd: Enumerate BTC_NO Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 72/89] x86/retbleed: Add fine grained Kconfig knobs Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 73/89] x86/bugs: Add Cannon lake to RETBleed affected CPU list Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 74/89] x86/entry: Move PUSH_AND_CLEAR_REGS() back into error_entry Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 75/89] x86/bugs: Do not enable IBPB-on-entry when IBPB is not supported Greg Kroah-Hartman
2022-07-22  9:11 ` Greg Kroah-Hartman [this message]
2022-07-22  9:11 ` [PATCH 5.15 77/89] x86/speculation: Disable RRSBA behavior Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 78/89] x86/static_call: Serialize __static_call_fixup() properly Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 79/89] x86/xen: Fix initialisation in hypercall_page after rethunk Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 80/89] x86/asm/32: Fix ANNOTATE_UNRET_SAFE use on 32-bit Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 81/89] x86/speculation: Use DECLARE_PER_CPU for x86_spec_ctrl_current Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 82/89] efi/x86: use naked RET on mixed mode call wrapper Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 83/89] x86/kvm: fix FASTOP_SIZE when return thunks are enabled Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 84/89] KVM: emulate: do not adjust size of fastop and setcc subroutines Greg Kroah-Hartman
2022-07-22  9:11 ` [PATCH 5.15 85/89] tools arch x86: Sync the msr-index.h copy with the kernel sources Greg Kroah-Hartman
2022-07-22  9:12 ` [PATCH 5.15 86/89] tools headers cpufeatures: Sync " Greg Kroah-Hartman
2022-07-22  9:12 ` [PATCH 5.15 87/89] x86/bugs: Remove apostrophe typo Greg Kroah-Hartman
2022-07-22  9:12 ` [PATCH 5.15 88/89] um: Add missing apply_returns() Greg Kroah-Hartman
2022-07-22  9:12 ` [PATCH 5.15 89/89] x86: Use -mindirect-branch-cs-prefix for RETPOLINE builds Greg Kroah-Hartman
2022-07-22 12:14 ` [PATCH 5.15 00/89] 5.15.57-rc1 review Bagas Sanjaya
2022-07-22 17:58 ` Florian Fainelli
2022-07-22 19:36 ` Naresh Kamboju
2022-07-22 21:59 ` Guenter Roeck
2022-07-23  4:21 ` Ron Economos
2022-07-23  8:55 ` Sudip Mukherjee (Codethink)

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