From: Borislav Petkov <bp@alien8.de> To: Andy Lutomirski <luto@kernel.org> Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>, Sean Christopherson <seanjc@google.com>, kernel test robot <oliver.sang@intel.com>, Josh Poimboeuf <jpoimboe@redhat.com>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, the arch/x86 maintainers <x86@kernel.org>, lkp@lists.01.org, lkp@intel.com Subject: Re: [PATCH] x86/entry_32: Fix segment exceptions Date: Sat, 15 Jan 2022 09:13:24 +0100 [thread overview] Message-ID: <YeKCJHju0owRVFoT@zn.tnic> (raw) In-Reply-To: <760ea801-8394-4e0c-9ec3-23e36e436551@www.fastmail.com> On Fri, Jan 14, 2022 at 03:48:31PM -0800, Andy Lutomirski wrote: > Acked-by: Andy Lutomirski <luto@kernel.org> I actually did this new version: --- From: Borislav Petkov <bp@suse.de> Subject: [PATCH] x86/entry_32: Remove GS from the pt_regs offsets and fixup regs Document how GS (and its stack slot) on 32-bit are used. Fixes: 9cdbeec40968 ("x86/entry_32: Fix segment exceptions") Signed-off-by: Borislav Petkov <bp@suse.de> --- arch/x86/entry/entry_32.S | 4 +++- arch/x86/include/asm/extable_fixup_types.h | 5 +++-- arch/x86/lib/insn-eval.c | 5 ++++- 3 files changed, 10 insertions(+), 4 deletions(-) diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S index a7ec22b1d06c..addc3966ee20 100644 --- a/arch/x86/entry/entry_32.S +++ b/arch/x86/entry/entry_32.S @@ -20,7 +20,9 @@ * 1C(%esp) - %ds * 20(%esp) - %es * 24(%esp) - %fs - * 28(%esp) - unused -- was %gs on old stackprotector kernels + * 28(%esp) - unused -- was %gs on old stackprotector kernels. %gs is unused in + * kernel mode in 32-bit and holds the user value. When handling exceptions, the + * C-exception handler address is pushed into the GS-slot on the stack. * 2C(%esp) - orig_eax * 30(%esp) - %eip * 34(%esp) - %cs diff --git a/arch/x86/include/asm/extable_fixup_types.h b/arch/x86/include/asm/extable_fixup_types.h index 503622627400..0aa5f4d3234f 100644 --- a/arch/x86/include/asm/extable_fixup_types.h +++ b/arch/x86/include/asm/extable_fixup_types.h @@ -20,11 +20,12 @@ #define EX_DATA_FLAG(flag) ((flag) << EX_DATA_FLAG_SHIFT) #define EX_DATA_IMM(imm) ((imm) << EX_DATA_IMM_SHIFT) -/* segment regs */ +#ifdef CONFIG_X86_32 +/* segment regs, valid only for 32-bit code, see pt_regoff */ #define EX_REG_DS EX_DATA_REG(8) #define EX_REG_ES EX_DATA_REG(9) #define EX_REG_FS EX_DATA_REG(10) -#define EX_REG_GS EX_DATA_REG(11) +#endif /* flags */ #define EX_FLAG_CLEAR_AX EX_DATA_FLAG(1) diff --git a/arch/x86/lib/insn-eval.c b/arch/x86/lib/insn-eval.c index b781d324211b..cfc4d13b7d5b 100644 --- a/arch/x86/lib/insn-eval.c +++ b/arch/x86/lib/insn-eval.c @@ -432,7 +432,10 @@ static const int pt_regoff[] = { offsetof(struct pt_regs, ds), offsetof(struct pt_regs, es), offsetof(struct pt_regs, fs), - offsetof(struct pt_regs, gs), + /* + * Can't use that one, see top of entry_32.S + * offsetof(struct pt_regs, gs), + */ #endif }; -- 2.29.2 -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette
WARNING: multiple messages have this Message-ID (diff)
From: Borislav Petkov <bp@alien8.de> To: lkp@lists.01.org Subject: Re: [PATCH] x86/entry_32: Fix segment exceptions Date: Sat, 15 Jan 2022 09:13:24 +0100 [thread overview] Message-ID: <YeKCJHju0owRVFoT@zn.tnic> (raw) In-Reply-To: <760ea801-8394-4e0c-9ec3-23e36e436551@www.fastmail.com> [-- Attachment #1: Type: text/plain, Size: 2579 bytes --] On Fri, Jan 14, 2022 at 03:48:31PM -0800, Andy Lutomirski wrote: > Acked-by: Andy Lutomirski <luto@kernel.org> I actually did this new version: --- From: Borislav Petkov <bp@suse.de> Subject: [PATCH] x86/entry_32: Remove GS from the pt_regs offsets and fixup regs Document how GS (and its stack slot) on 32-bit are used. Fixes: 9cdbeec40968 ("x86/entry_32: Fix segment exceptions") Signed-off-by: Borislav Petkov <bp@suse.de> --- arch/x86/entry/entry_32.S | 4 +++- arch/x86/include/asm/extable_fixup_types.h | 5 +++-- arch/x86/lib/insn-eval.c | 5 ++++- 3 files changed, 10 insertions(+), 4 deletions(-) diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S index a7ec22b1d06c..addc3966ee20 100644 --- a/arch/x86/entry/entry_32.S +++ b/arch/x86/entry/entry_32.S @@ -20,7 +20,9 @@ * 1C(%esp) - %ds * 20(%esp) - %es * 24(%esp) - %fs - * 28(%esp) - unused -- was %gs on old stackprotector kernels + * 28(%esp) - unused -- was %gs on old stackprotector kernels. %gs is unused in + * kernel mode in 32-bit and holds the user value. When handling exceptions, the + * C-exception handler address is pushed into the GS-slot on the stack. * 2C(%esp) - orig_eax * 30(%esp) - %eip * 34(%esp) - %cs diff --git a/arch/x86/include/asm/extable_fixup_types.h b/arch/x86/include/asm/extable_fixup_types.h index 503622627400..0aa5f4d3234f 100644 --- a/arch/x86/include/asm/extable_fixup_types.h +++ b/arch/x86/include/asm/extable_fixup_types.h @@ -20,11 +20,12 @@ #define EX_DATA_FLAG(flag) ((flag) << EX_DATA_FLAG_SHIFT) #define EX_DATA_IMM(imm) ((imm) << EX_DATA_IMM_SHIFT) -/* segment regs */ +#ifdef CONFIG_X86_32 +/* segment regs, valid only for 32-bit code, see pt_regoff */ #define EX_REG_DS EX_DATA_REG(8) #define EX_REG_ES EX_DATA_REG(9) #define EX_REG_FS EX_DATA_REG(10) -#define EX_REG_GS EX_DATA_REG(11) +#endif /* flags */ #define EX_FLAG_CLEAR_AX EX_DATA_FLAG(1) diff --git a/arch/x86/lib/insn-eval.c b/arch/x86/lib/insn-eval.c index b781d324211b..cfc4d13b7d5b 100644 --- a/arch/x86/lib/insn-eval.c +++ b/arch/x86/lib/insn-eval.c @@ -432,7 +432,10 @@ static const int pt_regoff[] = { offsetof(struct pt_regs, ds), offsetof(struct pt_regs, es), offsetof(struct pt_regs, fs), - offsetof(struct pt_regs, gs), + /* + * Can't use that one, see top of entry_32.S + * offsetof(struct pt_regs, gs), + */ #endif }; -- 2.29.2 -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette
next prev parent reply other threads:[~2022-01-15 8:13 UTC|newest] Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-01-06 8:35 [x86/entry_32] aa93e2ad74: BUG:soft_lockup-CPU##stuck_for#s![systemd-logind:#] kernel test robot 2022-01-06 8:35 ` kernel test robot 2022-01-11 11:11 ` Peter Zijlstra 2022-01-11 11:11 ` Peter Zijlstra 2022-01-12 1:28 ` Sean Christopherson 2022-01-12 1:28 ` Sean Christopherson 2022-01-12 10:25 ` Peter Zijlstra 2022-01-12 10:25 ` Peter Zijlstra 2022-01-12 16:14 ` Sean Christopherson 2022-01-12 16:14 ` Sean Christopherson 2022-01-12 10:55 ` [PATCH] x86/entry_32: Fix segment exceptions Peter Zijlstra 2022-01-12 10:55 ` Peter Zijlstra 2022-01-12 15:42 ` Borislav Petkov 2022-01-12 15:42 ` Borislav Petkov 2022-01-13 18:54 ` Andy Lutomirski 2022-01-13 18:54 ` Andy Lutomirski 2022-01-13 19:55 ` Peter Zijlstra 2022-01-13 19:55 ` Peter Zijlstra 2022-01-14 11:24 ` Borislav Petkov 2022-01-14 11:24 ` Borislav Petkov 2022-01-14 23:48 ` Andy Lutomirski 2022-01-14 23:48 ` Andy Lutomirski 2022-01-15 8:13 ` Borislav Petkov [this message] 2022-01-15 8:13 ` Borislav Petkov
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=YeKCJHju0owRVFoT@zn.tnic \ --to=bp@alien8.de \ --cc=jpoimboe@redhat.com \ --cc=linux-kernel@vger.kernel.org \ --cc=lkp@intel.com \ --cc=lkp@lists.01.org \ --cc=luto@kernel.org \ --cc=oliver.sang@intel.com \ --cc=peterz@infradead.org \ --cc=seanjc@google.com \ --cc=x86@kernel.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.