From 7bbcdb1ca4d2fd69094ee89c18601b396531ca9f Mon Sep 17 00:00:00 2001 From: Andy Lutomirski Date: Sat, 2 Apr 2016 07:01:32 -0700 Subject: 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 Signed-off-by: Andy Lutomirski Acked-by: Linus Torvalds Cc: Andrew Morton Cc: Arjan van de Ven Cc: Borislav Petkov Cc: KVM list Cc: Paolo Bonzini Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: xen-devel Link: http://lkml.kernel.org/r/e3fb680fcfd5e23e38237e8328b64a25cc121d37.1459605520.git.luto@kernel.org Signed-off-by: Ingo Molnar --- arch/x86/kernel/head_64.S | 68 ++++++++++++++++++++++++++--------------------- 1 file changed, 37 insertions(+), 31 deletions(-) (limited to 'arch/x86/kernel/head_64.S') 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 #include #include +#include "../entry/calling.h" #ifdef CONFIG_PARAVIRT #include @@ -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 -- cgit v1.1