search for: espfix

OK, here it is. Benchmarks still coming. This is against Andi's 2.6.18-rc7-git3 tree, and replaces the patches between (and not including) i386-pda-asm-offsets and i386-early-fault. One patch is identical, one is mildly modified, the rest are re-implemented but inspired by Jeremy's PDA work. Thanks, Rusty. -- Help! Save Australia from the worst of the DMCA: http://linux.org.au/law

OK, here it is. Benchmarks still coming. This is against Andi's 2.6.18-rc7-git3 tree, and replaces the patches between (and not including) i386-pda-asm-offsets and i386-early-fault. One patch is identical, one is mildly modified, the rest are re-implemented but inspired by Jeremy's PDA work. Thanks, Rusty. -- Help! Save Australia from the worst of the DMCA: http://linux.org.au/law

...0000 /* 0xc0 APM CS 16 code (16 bit) */ - .quad 0x0040920000000000 /* 0xc8 APM DS data */ + .quad 0x00409a000000ffff /* 0xb8 APM CS code */ + .quad 0x00009a000000ffff /* 0xc0 APM CS 16 code (16 bit) */ + .quad 0x004092000000ffff /* 0xc8 APM DS data */ .quad 0x0000920000000000 /* 0xd0 - ESPFIX 16-bit SS */ .quad 0x0000000000000000 /* 0xd8 - unused */ Index: linux-2.6.14-zach-work/arch/i386/kernel/apm.c =================================================================== --- linux-2.6.14-zach-work.orig/arch/i386/kernel/apm.c 2005-11-04 15:46:50.000000000 -0800 +++ linux-2.6.14-zach-work/...

...0000 /* 0xc0 APM CS 16 code (16 bit) */ - .quad 0x0040920000000000 /* 0xc8 APM DS data */ + .quad 0x00409a000000ffff /* 0xb8 APM CS code */ + .quad 0x00009a000000ffff /* 0xc0 APM CS 16 code (16 bit) */ + .quad 0x004092000000ffff /* 0xc8 APM DS data */ .quad 0x0000920000000000 /* 0xd0 - ESPFIX 16-bit SS */ .quad 0x0000000000000000 /* 0xd8 - unused */ Index: linux-2.6.14-zach-work/arch/i386/kernel/apm.c =================================================================== --- linux-2.6.14-zach-work.orig/arch/i386/kernel/apm.c 2005-11-04 15:46:50.000000000 -0800 +++ linux-2.6.14-zach-work/...

...ong address); +extern void early_idt_setup_early_handler(unsigned long physaddr); +extern void early_load_idt(void); #ifdef CONFIG_X86_INTEL_MID extern void x86_intel_mid_early_setup(void); @@ -66,6 +68,7 @@ static inline void x86_ce4100_early_setup(void) { } #ifndef _SETUP #include <asm/espfix.h> +#include <asm/sections.h> #include <linux/kernel.h> /* diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c index 8703292a35e9..096b09d06d1c 100644 --- a/arch/x86/kernel/head64.c +++ b/arch/x86/kernel/head64.c @@ -286,6 +286,9 @@ unsigned long __head __startup_64(...

...call early_load_idt diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 27aa04a95702..fb55d28332e2 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -1040,6 +1040,12 @@ static int do_boot_cpu(int apicid, int cpu, struct task_struct *idle, /* Enable the espfix hack for this CPU */ init_espfix_ap(cpu); + /* Set up GDT_ENTRY_CPUNODE for early exception handling */ + setup_getcpu(cpu); + + /* Setup TSS so that AP can use IST early */ + tss_setup(cpu); + /* So we see what's up */ announce_cpu(cpu, apicid); -- 2.28.0

Hi Jeremy, all, Sorry this took so long, spent last week in Japan at OSDL conf then netconf. After several false starts, I ended up with a very simple implementation, which clashes significantly with your work since then 8(. I've pushed the patches anyway, but it's going to be significant work for me to re-merge them, so I wanted your feedback first. The first patch simply changes

Hi Jeremy, all, Sorry this took so long, spent last week in Japan at OSDL conf then netconf. After several false starts, I ended up with a very simple implementation, which clashes significantly with your work since then 8(. I've pushed the patches anyway, but it's going to be significant work for me to re-merge them, so I wanted your feedback first. The first patch simply changes

..." + INTERRUPT_RETURN + iret_exc: TRACE_IRQS_ON ENABLE_INTERRUPTS(CLBR_NONE) pushl $0 # no error code pushl $do_iret_error jmp error_code -.previous -.section __ex_table,"a" - .align 4 - .long 1b,iret_exc -.previous CFI_RESTORE_STATE ldt_ss: @@ -863,21 +855,22 @@ nmi_espfix_stack: RESTORE_REGS lss 12+4(%esp), %esp # back to espfix stack CFI_ADJUST_CFA_OFFSET -24 -1: INTERRUPT_RETURN - CFI_ENDPROC + INTERRUPT_RETURN + CFI_ENDPROC +KPROBE_END(nmi) + +#ifdef CONFIG_PARAVIRT +ENTRY(native_iret) +1: popl %fs +2: iret +.pushsection .fixup,"ax" +3: movl $0,(...

..." + INTERRUPT_RETURN + iret_exc: TRACE_IRQS_ON ENABLE_INTERRUPTS(CLBR_NONE) pushl $0 # no error code pushl $do_iret_error jmp error_code -.previous -.section __ex_table,"a" - .align 4 - .long 1b,iret_exc -.previous CFI_RESTORE_STATE ldt_ss: @@ -863,21 +855,22 @@ nmi_espfix_stack: RESTORE_REGS lss 12+4(%esp), %esp # back to espfix stack CFI_ADJUST_CFA_OFFSET -24 -1: INTERRUPT_RETURN - CFI_ENDPROC + INTERRUPT_RETURN + CFI_ENDPROC +KPROBE_END(nmi) + +#ifdef CONFIG_PARAVIRT +ENTRY(native_iret) +1: popl %fs +2: iret +.pushsection .fixup,"ax" +3: movl $0,(...

On Tue, Jun 23, 2020 at 04:59:14PM +0200, Joerg Roedel wrote: > On Tue, Jun 23, 2020 at 04:53:44PM +0200, Peter Zijlstra wrote: > > +noinstr void idtentry_validate_ist(struct pt_regs *regs) > > +{ > > + if ((regs->sp & ~(EXCEPTION_STKSZ-1)) == > > + (_RET_IP_ & ~(EXCEPTION_STKSZ-1))) > > + die("IST stack recursion", regs, 0); > > +}

..._exit + + /* Switch to the regular task stack */ +.Lfrom_usermode_switch_stack_\@: + idtentry_body safe_stack_\cfunc, has_error_code=1 + +_ASM_NOKPROBE(\asmsym) +SYM_CODE_END(\asmsym) +.endm + /* * Double fault entry. Straight paranoid. No checks from which context * this comes because for the espfix induced #DF this would do the wrong diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h index 337dcfd45472..5ce67113a761 100644 --- a/arch/x86/include/asm/idtentry.h +++ b/arch/x86/include/asm/idtentry.h @@ -308,6 +308,18 @@ static __always_inline void __##func(struct pt_...

...#define NUM_EXCEPTION_VECTORS 32 diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 965474d78cef..ca89cea31e81 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1412,15 +1412,7 @@ static void generic_identify(struct cpuinfo_x86 *c) * ESPFIX issue, we can change this. */ #ifdef CONFIG_X86_32 -# ifdef CONFIG_PARAVIRT_XXL - do { - extern void native_iret(void); - if (pv_ops.cpu.iret == native_iret) - set_cpu_bug(c, X86_BUG_ESPFIX); - } while (0); -# else set_cpu_bug(c, X86_BUG_ESPFIX); -# endif #endif } diff --git a/arch/x8...

...#define NUM_EXCEPTION_VECTORS 32 diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index c5d6f17d9b9d..8aa20bc2f1ca 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1413,15 +1413,7 @@ static void generic_identify(struct cpuinfo_x86 *c) * ESPFIX issue, we can change this. */ #ifdef CONFIG_X86_32 -# ifdef CONFIG_PARAVIRT_XXL - do { - extern void native_iret(void); - if (pv_ops.cpu.iret == native_iret) - set_cpu_bug(c, X86_BUG_ESPFIX); - } while (0); -# else set_cpu_bug(c, X86_BUG_ESPFIX); -# endif #endif } diff --git a/arch/x8...

The long term plan has been to replace Xen PV guests by PVH. The first victim of that plan are now 32-bit PV guests, as those are used only rather seldom these days. Xen on x86 requires 64-bit support and with Grub2 now supporting PVH officially since version 2.04 there is no need to keep 32-bit PV guest support alive in the Linux kernel. Additionally Meltdown mitigation is not available in the

The long term plan has been to replace Xen PV guests by PVH. The first victim of that plan are now 32-bit PV guests, as those are used only rather seldom these days. Xen on x86 requires 64-bit support and with Grub2 now supporting PVH officially since version 2.04 there is no need to keep 32-bit PV guest support alive in the Linux kernel. Additionally Meltdown mitigation is not available in the

The long term plan has been to replace Xen PV guests by PVH. The first victim of that plan are now 32-bit PV guests, as those are used only rather seldom these days. Xen on x86 requires 64-bit support and with Grub2 now supporting PVH officially since version 2.04 there is no need to keep 32-bit PV guest support alive in the Linux kernel. Additionally Meltdown mitigation is not available in the

The long term plan has been to replace Xen PV guests by PVH. The first victim of that plan are now 32-bit PV guests, as those are used only rather seldom these days. Xen on x86 requires 64-bit support and with Grub2 now supporting PVH officially since version 2.04 there is no need to keep 32-bit PV guest support alive in the Linux kernel. Additionally Meltdown mitigation is not available in the

The long term plan has been to replace Xen PV guests by PVH. The first victim of that plan are now 32-bit PV guests, as those are used only rather seldom these days. Xen on x86 requires 64-bit support and with Grub2 now supporting PVH officially since version 2.04 there is no need to keep 32-bit PV guest support alive in the Linux kernel. Additionally Meltdown mitigation is not available in the

A lot of cleanup after removal of 32-bit Xen PV guest support in paravirt code. Changes in V4: - dropped patches 1-3, as already committed - addressed comments to V3 - added new patches 5+6 Changes in V3: - addressed comments to V2 - split patch 1 into 2 patches - new patches 3 and 7 Changes in V2: - rebase to 5.8 kernel - addressed comments to V1 - new patches 3 and 4 Juergen Gross (6):