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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [tip:x86/asm] x86/head: Pass a real pt_regs and trapnr to early_fixup_exception()
Commit-ID: 7bbcdb1ca4d2fd69094ee89c18601b396531ca9f Gitweb: http://git.kernel.org/tip/7bbcdb1ca4d2fd69094ee89c18601b396531ca9f Author: Andy Lutomirski <luto@xxxxxxxxxx> AuthorDate: Sat, 2 Apr 2016 07:01:32 -0700 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitDate: Wed, 13 Apr 2016 11:37:44 +0200 x86/head: Pass a real pt_regs and trapnr to early_fixup_exception() early_fixup_exception() is limited by the fact that it doesn't have a real struct pt_regs. Change both the 32-bit and 64-bit asm and the C code to pass and accept a real pt_regs. Tested-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx> Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx> Acked-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Cc: Arjan van de Ven <arjan@xxxxxxxxxxxxxxx> Cc: Borislav Petkov <bp@xxxxxxxxx> Cc: KVM list <kvm@xxxxxxxxxxxxxxx> Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: xen-devel <Xen-devel@xxxxxxxxxxxxx> Link: http://lkml.kernel.org/r/e3fb680fcfd5e23e38237e8328b64a25cc121d37.1459605520.git.luto@xxxxxxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> --- arch/x86/include/asm/uaccess.h | 2 +- arch/x86/kernel/head_32.S | 74 +++++++++++++++++++++++++++++------------- arch/x86/kernel/head_64.S | 68 ++++++++++++++++++++------------------ arch/x86/mm/extable.c | 6 ++-- 4 files changed, 92 insertions(+), 58 deletions(-) diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h index a969ae6..b6fb311 100644 --- a/arch/x86/include/asm/uaccess.h +++ b/arch/x86/include/asm/uaccess.h @@ -110,7 +110,7 @@ struct exception_table_entry { extern int fixup_exception(struct pt_regs *regs, int trapnr); extern bool ex_has_fault_handler(unsigned long ip); -extern int early_fixup_exception(unsigned long *ip); +extern int early_fixup_exception(struct pt_regs *regs, int trapnr); /* * These are the main single-value transfer routines. They automatically diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S index 54cdbd2..0904536 100644 --- a/arch/x86/kernel/head_32.S +++ b/arch/x86/kernel/head_32.S @@ -568,29 +568,64 @@ early_idt_handler_common: je hlt_loop incl %ss:early_recursion_flag - push %eax # 16(%esp) - push %ecx # 12(%esp) - push %edx # 8(%esp) - push %ds # 4(%esp) - push %es # 0(%esp) - movl $(__KERNEL_DS),%eax - movl %eax,%ds - movl %eax,%es + /* The vector number is in pt_regs->gs */ - cmpl $(__KERNEL_CS),32(%esp) + cld + pushl %fs /* pt_regs->fs */ + movw $0, 2(%esp) /* clear high bits (some CPUs leave garbage) */ + pushl %es /* pt_regs->es */ + movw $0, 2(%esp) /* clear high bits (some CPUs leave garbage) */ + pushl %ds /* pt_regs->ds */ + movw $0, 2(%esp) /* clear high bits (some CPUs leave garbage) */ + pushl %eax /* pt_regs->ax */ + pushl %ebp /* pt_regs->bp */ + pushl %edi /* pt_regs->di */ + pushl %esi /* pt_regs->si */ + pushl %edx /* pt_regs->dx */ + pushl %ecx /* pt_regs->cx */ + pushl %ebx /* pt_regs->bx */ + + /* Fix up DS and ES */ + movl $(__KERNEL_DS), %ecx + movl %ecx, %ds + movl %ecx, %es + + /* Load the vector number into EDX */ + movl PT_GS(%esp), %edx + + /* Load GS into pt_regs->gs and clear high bits */ + movw %gs, PT_GS(%esp) + movw $0, PT_GS+2(%esp) + + cmpl $(__KERNEL_CS),PT_CS(%esp) jne 10f - leal 28(%esp),%eax # Pointer to %eip - call early_fixup_exception - andl %eax,%eax - jnz ex_entry /* found an exception entry */ + movl %esp, %eax /* args are pt_regs (EAX), trapnr (EDX) */ + call early_fixup_exception + andl %eax,%eax + jz 10f /* Exception wasn't fixed up */ + + popl %ebx /* pt_regs->bx */ + popl %ecx /* pt_regs->cx */ + popl %edx /* pt_regs->dx */ + popl %esi /* pt_regs->si */ + popl %edi /* pt_regs->di */ + popl %ebp /* pt_regs->bp */ + popl %eax /* pt_regs->ax */ + popl %ds /* pt_regs->ds */ + popl %es /* pt_regs->es */ + popl %fs /* pt_regs->fs */ + popl %gs /* pt_regs->gs */ + decl %ss:early_recursion_flag + addl $4, %esp /* pop pt_regs->orig_ax */ + iret 10: #ifdef CONFIG_PRINTK xorl %eax,%eax - movw %ax,2(%esp) /* clean up the segment values on some cpus */ - movw %ax,6(%esp) - movw %ax,34(%esp) + movw %ax,PT_FS+2(%esp) /* clean up the segment values on some cpus */ + movw %ax,PT_DS+2(%esp) + movw %ax,PT_ES+2(%esp) leal 40(%esp),%eax pushl %eax /* %esp before the exception */ pushl %ebx @@ -608,13 +643,6 @@ hlt_loop: hlt jmp hlt_loop -ex_entry: - pop %es - pop %ds - pop %edx - pop %ecx - pop %eax - decl %ss:early_recursion_flag .Lis_nmi: addl $8,%esp /* drop vector number and error code */ iret diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S index 22fbf9d..9e8636d 100644 --- a/arch/x86/kernel/head_64.S +++ b/arch/x86/kernel/head_64.S @@ -20,6 +20,7 @@ #include <asm/processor-flags.h> #include <asm/percpu.h> #include <asm/nops.h> +#include "../entry/calling.h" #ifdef CONFIG_PARAVIRT #include <asm/asm-offsets.h> @@ -357,39 +358,52 @@ early_idt_handler_common: jz 1f incl early_recursion_flag(%rip) - pushq %rax # 64(%rsp) - pushq %rcx # 56(%rsp) - pushq %rdx # 48(%rsp) - pushq %rsi # 40(%rsp) - pushq %rdi # 32(%rsp) - pushq %r8 # 24(%rsp) - pushq %r9 # 16(%rsp) - pushq %r10 # 8(%rsp) - pushq %r11 # 0(%rsp) - - cmpl $__KERNEL_CS,96(%rsp) + /* The vector number is currently in the pt_regs->di slot. */ + pushq %rsi /* pt_regs->si */ + movq 8(%rsp), %rsi /* RSI = vector number */ + movq %rdi, 8(%rsp) /* pt_regs->di = RDI */ + pushq %rdx /* pt_regs->dx */ + pushq %rcx /* pt_regs->cx */ + pushq %rax /* pt_regs->ax */ + pushq %r8 /* pt_regs->r8 */ + pushq %r9 /* pt_regs->r9 */ + pushq %r10 /* pt_regs->r10 */ + pushq %r11 /* pt_regs->r11 */ + pushq %rbx /* pt_regs->bx */ + pushq %rbp /* pt_regs->bp */ + pushq %r12 /* pt_regs->r12 */ + pushq %r13 /* pt_regs->r13 */ + pushq %r14 /* pt_regs->r14 */ + pushq %r15 /* pt_regs->r15 */ + + cmpl $__KERNEL_CS,CS(%rsp) jne 11f - cmpl $14,72(%rsp) # Page fault? + cmpq $14,%rsi /* Page fault? */ jnz 10f - GET_CR2_INTO(%rdi) # can clobber any volatile register if pv + GET_CR2_INTO(%rdi) /* Can clobber any volatile register if pv */ call early_make_pgtable andl %eax,%eax - jz 20f # All good + jz 20f /* All good */ 10: - leaq 88(%rsp),%rdi # Pointer to %rip + movq %rsp,%rdi /* RDI = pt_regs; RSI is already trapnr */ call early_fixup_exception andl %eax,%eax jnz 20f # Found an exception entry 11: #ifdef CONFIG_EARLY_PRINTK - GET_CR2_INTO(%r9) # can clobber any volatile register if pv - movl 80(%rsp),%r8d # error code - movl 72(%rsp),%esi # vector number - movl 96(%rsp),%edx # %cs - movq 88(%rsp),%rcx # %rip + /* + * On paravirt kernels, GET_CR2_INTO clobbers callee-clobbered regs. + * We only care about RSI, so we need to save it. + */ + movq %rsi,%rbx /* Save vector number */ + GET_CR2_INTO(%r9) + movq ORIG_RAX(%rsp),%r8 /* error code */ + movq %rbx,%rsi /* vector number */ + movq CS(%rsp),%rdx + movq RIP(%rsp),%rcx xorl %eax,%eax leaq early_idt_msg(%rip),%rdi call early_printk @@ -398,24 +412,16 @@ early_idt_handler_common: call dump_stack #ifdef CONFIG_KALLSYMS leaq early_idt_ripmsg(%rip),%rdi - movq 40(%rsp),%rsi # %rip again + movq RIP(%rsp),%rsi # %rip again call __print_symbol #endif #endif /* EARLY_PRINTK */ 1: hlt jmp 1b -20: # Exception table entry found or page table generated - popq %r11 - popq %r10 - popq %r9 - popq %r8 - popq %rdi - popq %rsi - popq %rdx - popq %rcx - popq %rax +20: /* Exception table entry found or page table generated */ decl early_recursion_flag(%rip) + jmp restore_regs_and_iret .Lis_nmi: addq $16,%rsp # drop vector number and error code INTERRUPT_RETURN diff --git a/arch/x86/mm/extable.c b/arch/x86/mm/extable.c index 82447b3..1366e06 100644 --- a/arch/x86/mm/extable.c +++ b/arch/x86/mm/extable.c @@ -83,13 +83,13 @@ int fixup_exception(struct pt_regs *regs, int trapnr) } /* Restricted version used during very early boot */ -int __init early_fixup_exception(unsigned long *ip) +int __init early_fixup_exception(struct pt_regs *regs, int trapnr) { const struct exception_table_entry *e; unsigned long new_ip; ex_handler_t handler; - e = search_exception_tables(*ip); + e = search_exception_tables(regs->ip); if (!e) return 0; @@ -100,6 +100,6 @@ int __init early_fixup_exception(unsigned long *ip) if (handler != ex_handler_default) return 0; - *ip = new_ip; + regs->ip = new_ip; return 1; } _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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