obj-y += vdso/
obj-y += vsyscall/
-obj-$(CONFIG_IA32_EMULATION) += ia32entry.o syscall_32.o
+obj-$(CONFIG_IA32_EMULATION) += entry_64_compat.o syscall_32.o
/*
* By the time we get here, we have no idea whether our pt_regs,
* ti flags, and ti status came from the 64-bit SYSCALL fast path,
- * the slow path, or one of the ia32entry paths.
+ * the slow path, or one of the 32-bit compat paths.
* Use IRET code path to return, since it can safely handle
* all of the above.
*/
--- /dev/null
+/*
+ * Compatibility mode system call entry point for x86-64.
+ *
+ * Copyright 2000-2002 Andi Kleen, SuSE Labs.
+ */
+#include "calling.h"
+#include <asm/asm-offsets.h>
+#include <asm/current.h>
+#include <asm/errno.h>
+#include <asm/ia32_unistd.h>
+#include <asm/thread_info.h>
+#include <asm/segment.h>
+#include <asm/irqflags.h>
+#include <asm/asm.h>
+#include <asm/smap.h>
+#include <linux/linkage.h>
+#include <linux/err.h>
+
+/* Avoid __ASSEMBLER__'ifying <linux/audit.h> just for this. */
+#include <linux/elf-em.h>
+#define AUDIT_ARCH_I386 (EM_386|__AUDIT_ARCH_LE)
+#define __AUDIT_ARCH_LE 0x40000000
+
+#ifndef CONFIG_AUDITSYSCALL
+# define sysexit_audit ia32_ret_from_sys_call
+# define sysretl_audit ia32_ret_from_sys_call
+#endif
+
+ .section .entry.text, "ax"
+
+#ifdef CONFIG_PARAVIRT
+ENTRY(native_usergs_sysret32)
+ swapgs
+ sysretl
+ENDPROC(native_usergs_sysret32)
+#endif
+
+/*
+ * 32-bit SYSENTER instruction entry.
+ *
+ * SYSENTER loads ss, rsp, cs, and rip from previously programmed MSRs.
+ * IF and VM in rflags are cleared (IOW: interrupts are off).
+ * SYSENTER does not save anything on the stack,
+ * and does not save old rip (!!!) and rflags.
+ *
+ * Arguments:
+ * eax system call number
+ * ebx arg1
+ * ecx arg2
+ * edx arg3
+ * esi arg4
+ * edi arg5
+ * ebp user stack
+ * 0(%ebp) arg6
+ *
+ * This is purely a fast path. For anything complicated we use the int 0x80
+ * path below. We set up a complete hardware stack frame to share code
+ * with the int 0x80 path.
+ */
+ENTRY(ia32_sysenter_target)
+ /*
+ * Interrupts are off on entry.
+ * We do not frame this tiny irq-off block with TRACE_IRQS_OFF/ON,
+ * it is too small to ever cause noticeable irq latency.
+ */
+ SWAPGS_UNSAFE_STACK
+ movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
+ ENABLE_INTERRUPTS(CLBR_NONE)
+
+ /* Zero-extending 32-bit regs, do not remove */
+ movl %ebp, %ebp
+ movl %eax, %eax
+
+ movl ASM_THREAD_INFO(TI_sysenter_return, %rsp, 0), %r10d
+
+ /* Construct struct pt_regs on stack */
+ pushq $__USER32_DS /* pt_regs->ss */
+ pushq %rbp /* pt_regs->sp */
+ pushfq /* pt_regs->flags */
+ pushq $__USER32_CS /* pt_regs->cs */
+ pushq %r10 /* pt_regs->ip = thread_info->sysenter_return */
+ pushq %rax /* pt_regs->orig_ax */
+ pushq %rdi /* pt_regs->di */
+ pushq %rsi /* pt_regs->si */
+ pushq %rdx /* pt_regs->dx */
+ pushq %rcx /* pt_regs->cx */
+ pushq $-ENOSYS /* pt_regs->ax */
+ cld
+ sub $(10*8), %rsp /* pt_regs->r8-11, bp, bx, r12-15 not saved */
+
+ /*
+ * no need to do an access_ok check here because rbp has been
+ * 32-bit zero extended
+ */
+ ASM_STAC
+1: movl (%rbp), %ebp
+ _ASM_EXTABLE(1b, ia32_badarg)
+ ASM_CLAC
+
+ /*
+ * Sysenter doesn't filter flags, so we need to clear NT
+ * ourselves. To save a few cycles, we can check whether
+ * NT was set instead of doing an unconditional popfq.
+ */
+ testl $X86_EFLAGS_NT, EFLAGS(%rsp)
+ jnz sysenter_fix_flags
+sysenter_flags_fixed:
+
+ orl $TS_COMPAT, ASM_THREAD_INFO(TI_status, %rsp, SIZEOF_PTREGS)
+ testl $_TIF_WORK_SYSCALL_ENTRY, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
+ jnz sysenter_tracesys
+
+sysenter_do_call:
+ /* 32-bit syscall -> 64-bit C ABI argument conversion */
+ movl %edi, %r8d /* arg5 */
+ movl %ebp, %r9d /* arg6 */
+ xchg %ecx, %esi /* rsi:arg2, rcx:arg4 */
+ movl %ebx, %edi /* arg1 */
+ movl %edx, %edx /* arg3 (zero extension) */
+sysenter_dispatch:
+ cmpq $(IA32_NR_syscalls-1), %rax
+ ja 1f
+ call *ia32_sys_call_table(, %rax, 8)
+ movq %rax, RAX(%rsp)
+1:
+ DISABLE_INTERRUPTS(CLBR_NONE)
+ TRACE_IRQS_OFF
+ testl $_TIF_ALLWORK_MASK, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
+ jnz sysexit_audit
+sysexit_from_sys_call:
+ /*
+ * NB: SYSEXIT is not obviously safe for 64-bit kernels -- an
+ * NMI between STI and SYSEXIT has poorly specified behavior,
+ * and and NMI followed by an IRQ with usergs is fatal. So
+ * we just pretend we're using SYSEXIT but we really use
+ * SYSRETL instead.
+ *
+ * This code path is still called 'sysexit' because it pairs
+ * with 'sysenter' and it uses the SYSENTER calling convention.
+ */
+ andl $~TS_COMPAT, ASM_THREAD_INFO(TI_status, %rsp, SIZEOF_PTREGS)
+ movl RIP(%rsp), %ecx /* User %eip */
+ RESTORE_RSI_RDI
+ xorl %edx, %edx /* Do not leak kernel information */
+ xorq %r8, %r8
+ xorq %r9, %r9
+ xorq %r10, %r10
+ movl EFLAGS(%rsp), %r11d /* User eflags */
+ TRACE_IRQS_ON
+
+ /*
+ * SYSRETL works even on Intel CPUs. Use it in preference to SYSEXIT,
+ * since it avoids a dicey window with interrupts enabled.
+ */
+ movl RSP(%rsp), %esp
+
+ /*
+ * USERGS_SYSRET32 does:
+ * gsbase = user's gs base
+ * eip = ecx
+ * rflags = r11
+ * cs = __USER32_CS
+ * ss = __USER_DS
+ *
+ * The prologue set RIP(%rsp) to VDSO32_SYSENTER_RETURN, which does:
+ *
+ * pop %ebp
+ * pop %edx
+ * pop %ecx
+ *
+ * Therefore, we invoke SYSRETL with EDX and R8-R10 zeroed to
+ * avoid info leaks. R11 ends up with VDSO32_SYSENTER_RETURN's
+ * address (already known to user code), and R12-R15 are
+ * callee-saved and therefore don't contain any interesting
+ * kernel data.
+ */
+ USERGS_SYSRET32
+
+#ifdef CONFIG_AUDITSYSCALL
+ .macro auditsys_entry_common
+ movl %esi, %r8d /* 5th arg: 4th syscall arg */
+ movl %ecx, %r9d /* swap with edx */
+ movl %edx, %ecx /* 4th arg: 3rd syscall arg */
+ movl %r9d, %edx /* 3rd arg: 2nd syscall arg */
+ movl %ebx, %esi /* 2nd arg: 1st syscall arg */
+ movl %eax, %edi /* 1st arg: syscall number */
+ call __audit_syscall_entry
+ movl ORIG_RAX(%rsp), %eax /* reload syscall number */
+ movl %ebx, %edi /* reload 1st syscall arg */
+ movl RCX(%rsp), %esi /* reload 2nd syscall arg */
+ movl RDX(%rsp), %edx /* reload 3rd syscall arg */
+ movl RSI(%rsp), %ecx /* reload 4th syscall arg */
+ movl RDI(%rsp), %r8d /* reload 5th syscall arg */
+ .endm
+
+ .macro auditsys_exit exit
+ testl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT), ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
+ jnz ia32_ret_from_sys_call
+ TRACE_IRQS_ON
+ ENABLE_INTERRUPTS(CLBR_NONE)
+ movl %eax, %esi /* second arg, syscall return value */
+ cmpl $-MAX_ERRNO, %eax /* is it an error ? */
+ jbe 1f
+ movslq %eax, %rsi /* if error sign extend to 64 bits */
+1: setbe %al /* 1 if error, 0 if not */
+ movzbl %al, %edi /* zero-extend that into %edi */
+ call __audit_syscall_exit
+ movq RAX(%rsp), %rax /* reload syscall return value */
+ movl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT), %edi
+ DISABLE_INTERRUPTS(CLBR_NONE)
+ TRACE_IRQS_OFF
+ testl %edi, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
+ jz \exit
+ xorl %eax, %eax /* Do not leak kernel information */
+ movq %rax, R11(%rsp)
+ movq %rax, R10(%rsp)
+ movq %rax, R9(%rsp)
+ movq %rax, R8(%rsp)
+ jmp int_with_check
+ .endm
+
+sysenter_auditsys:
+ auditsys_entry_common
+ movl %ebp, %r9d /* reload 6th syscall arg */
+ jmp sysenter_dispatch
+
+sysexit_audit:
+ auditsys_exit sysexit_from_sys_call
+#endif
+
+sysenter_fix_flags:
+ pushq $(X86_EFLAGS_IF|X86_EFLAGS_FIXED)
+ popfq
+ jmp sysenter_flags_fixed
+
+sysenter_tracesys:
+#ifdef CONFIG_AUDITSYSCALL
+ testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT), ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
+ jz sysenter_auditsys
+#endif
+ SAVE_EXTRA_REGS
+ xorl %eax, %eax /* Do not leak kernel information */
+ movq %rax, R11(%rsp)
+ movq %rax, R10(%rsp)
+ movq %rax, R9(%rsp)
+ movq %rax, R8(%rsp)
+ movq %rsp, %rdi /* &pt_regs -> arg1 */
+ call syscall_trace_enter
+
+ /* Reload arg registers from stack. (see sysenter_tracesys) */
+ movl RCX(%rsp), %ecx
+ movl RDX(%rsp), %edx
+ movl RSI(%rsp), %esi
+ movl RDI(%rsp), %edi
+ movl %eax, %eax /* zero extension */
+
+ RESTORE_EXTRA_REGS
+ jmp sysenter_do_call
+ENDPROC(ia32_sysenter_target)
+
+/*
+ * 32-bit SYSCALL instruction entry.
+ *
+ * 32-bit SYSCALL saves rip to rcx, clears rflags.RF, then saves rflags to r11,
+ * then loads new ss, cs, and rip from previously programmed MSRs.
+ * rflags gets masked by a value from another MSR (so CLD and CLAC
+ * are not needed). SYSCALL does not save anything on the stack
+ * and does not change rsp.
+ *
+ * Note: rflags saving+masking-with-MSR happens only in Long mode
+ * (in legacy 32-bit mode, IF, RF and VM bits are cleared and that's it).
+ * Don't get confused: rflags saving+masking depends on Long Mode Active bit
+ * (EFER.LMA=1), NOT on bitness of userspace where SYSCALL executes
+ * or target CS descriptor's L bit (SYSCALL does not read segment descriptors).
+ *
+ * Arguments:
+ * eax system call number
+ * ecx return address
+ * ebx arg1
+ * ebp arg2 (note: not saved in the stack frame, should not be touched)
+ * edx arg3
+ * esi arg4
+ * edi arg5
+ * esp user stack
+ * 0(%esp) arg6
+ *
+ * This is purely a fast path. For anything complicated we use the int 0x80
+ * path below. We set up a complete hardware stack frame to share code
+ * with the int 0x80 path.
+ */
+ENTRY(ia32_cstar_target)
+ /*
+ * Interrupts are off on entry.
+ * We do not frame this tiny irq-off block with TRACE_IRQS_OFF/ON,
+ * it is too small to ever cause noticeable irq latency.
+ */
+ SWAPGS_UNSAFE_STACK
+ movl %esp, %r8d
+ movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
+ ENABLE_INTERRUPTS(CLBR_NONE)
+
+ /* Zero-extending 32-bit regs, do not remove */
+ movl %eax, %eax
+
+ /* Construct struct pt_regs on stack */
+ pushq $__USER32_DS /* pt_regs->ss */
+ pushq %r8 /* pt_regs->sp */
+ pushq %r11 /* pt_regs->flags */
+ pushq $__USER32_CS /* pt_regs->cs */
+ pushq %rcx /* pt_regs->ip */
+ pushq %rax /* pt_regs->orig_ax */
+ pushq %rdi /* pt_regs->di */
+ pushq %rsi /* pt_regs->si */
+ pushq %rdx /* pt_regs->dx */
+ pushq %rbp /* pt_regs->cx */
+ movl %ebp, %ecx
+ pushq $-ENOSYS /* pt_regs->ax */
+ sub $(10*8), %rsp /* pt_regs->r8-11, bp, bx, r12-15 not saved */
+
+ /*
+ * No need to do an access_ok check here because r8 has been
+ * 32-bit zero extended:
+ */
+ ASM_STAC
+1: movl (%r8), %ebp
+ _ASM_EXTABLE(1b, ia32_badarg)
+ ASM_CLAC
+ orl $TS_COMPAT, ASM_THREAD_INFO(TI_status, %rsp, SIZEOF_PTREGS)
+ testl $_TIF_WORK_SYSCALL_ENTRY, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
+ jnz cstar_tracesys
+
+cstar_do_call:
+ /* 32-bit syscall -> 64-bit C ABI argument conversion */
+ movl %edi, %r8d /* arg5 */
+ movl %ebp, %r9d /* arg6 */
+ xchg %ecx, %esi /* rsi:arg2, rcx:arg4 */
+ movl %ebx, %edi /* arg1 */
+ movl %edx, %edx /* arg3 (zero extension) */
+
+cstar_dispatch:
+ cmpq $(IA32_NR_syscalls-1), %rax
+ ja 1f
+
+ call *ia32_sys_call_table(, %rax, 8)
+ movq %rax, RAX(%rsp)
+1:
+ DISABLE_INTERRUPTS(CLBR_NONE)
+ TRACE_IRQS_OFF
+ testl $_TIF_ALLWORK_MASK, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
+ jnz sysretl_audit
+
+sysretl_from_sys_call:
+ andl $~TS_COMPAT, ASM_THREAD_INFO(TI_status, %rsp, SIZEOF_PTREGS)
+ movl RCX(%rsp), %ebp
+ RESTORE_RSI_RDI_RDX
+ movl RIP(%rsp), %ecx
+ movl EFLAGS(%rsp), %r11d
+ xorq %r10, %r10
+ xorq %r9, %r9
+ xorq %r8, %r8
+ TRACE_IRQS_ON
+ movl RSP(%rsp), %esp
+ /*
+ * 64-bit->32-bit SYSRET restores eip from ecx,
+ * eflags from r11 (but RF and VM bits are forced to 0),
+ * cs and ss are loaded from MSRs.
+ * (Note: 32-bit->32-bit SYSRET is different: since r11
+ * does not exist, it merely sets eflags.IF=1).
+ *
+ * NB: On AMD CPUs with the X86_BUG_SYSRET_SS_ATTRS bug, the ss
+ * descriptor is not reinitialized. This means that we must
+ * avoid SYSRET with SS == NULL, which could happen if we schedule,
+ * exit the kernel, and re-enter using an interrupt vector. (All
+ * interrupt entries on x86_64 set SS to NULL.) We prevent that
+ * from happening by reloading SS in __switch_to.
+ */
+ USERGS_SYSRET32
+
+#ifdef CONFIG_AUDITSYSCALL
+cstar_auditsys:
+ auditsys_entry_common
+ movl %ebp, %r9d /* reload 6th syscall arg */
+ jmp cstar_dispatch
+
+sysretl_audit:
+ auditsys_exit sysretl_from_sys_call
+#endif
+
+cstar_tracesys:
+#ifdef CONFIG_AUDITSYSCALL
+ testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT), ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
+ jz cstar_auditsys
+#endif
+ SAVE_EXTRA_REGS
+ xorl %eax, %eax /* Do not leak kernel information */
+ movq %rax, R11(%rsp)
+ movq %rax, R10(%rsp)
+ movq %rax, R9(%rsp)
+ movq %rax, R8(%rsp)
+ movq %rsp, %rdi /* &pt_regs -> arg1 */
+ call syscall_trace_enter
+
+ /* Reload arg registers from stack. (see sysenter_tracesys) */
+ movl RCX(%rsp), %ecx
+ movl RDX(%rsp), %edx
+ movl RSI(%rsp), %esi
+ movl RDI(%rsp), %edi
+ movl %eax, %eax /* zero extension */
+
+ RESTORE_EXTRA_REGS
+ jmp cstar_do_call
+END(ia32_cstar_target)
+
+ia32_badarg:
+ ASM_CLAC
+ movq $-EFAULT, %rax
+ jmp ia32_sysret
+
+ia32_ret_from_sys_call:
+ xorl %eax, %eax /* Do not leak kernel information */
+ movq %rax, R11(%rsp)
+ movq %rax, R10(%rsp)
+ movq %rax, R9(%rsp)
+ movq %rax, R8(%rsp)
+ jmp int_ret_from_sys_call
+
+/*
+ * Emulated IA32 system calls via int 0x80.
+ *
+ * Arguments:
+ * eax system call number
+ * ebx arg1
+ * ecx arg2
+ * edx arg3
+ * esi arg4
+ * edi arg5
+ * ebp arg6 (note: not saved in the stack frame, should not be touched)
+ *
+ * Notes:
+ * Uses the same stack frame as the x86-64 version.
+ * All registers except eax must be saved (but ptrace may violate that).
+ * Arguments are zero extended. For system calls that want sign extension and
+ * take long arguments a wrapper is needed. Most calls can just be called
+ * directly.
+ * Assumes it is only called from user space and entered with interrupts off.
+ */
+
+ENTRY(ia32_syscall)
+ /*
+ * Interrupts are off on entry.
+ * We do not frame this tiny irq-off block with TRACE_IRQS_OFF/ON,
+ * it is too small to ever cause noticeable irq latency.
+ */
+ PARAVIRT_ADJUST_EXCEPTION_FRAME
+ SWAPGS
+ ENABLE_INTERRUPTS(CLBR_NONE)
+
+ /* Zero-extending 32-bit regs, do not remove */
+ movl %eax, %eax
+
+ /* Construct struct pt_regs on stack (iret frame is already on stack) */
+ pushq %rax /* pt_regs->orig_ax */
+ pushq %rdi /* pt_regs->di */
+ pushq %rsi /* pt_regs->si */
+ pushq %rdx /* pt_regs->dx */
+ pushq %rcx /* pt_regs->cx */
+ pushq $-ENOSYS /* pt_regs->ax */
+ pushq $0 /* pt_regs->r8 */
+ pushq $0 /* pt_regs->r9 */
+ pushq $0 /* pt_regs->r10 */
+ pushq $0 /* pt_regs->r11 */
+ cld
+ sub $(6*8), %rsp /* pt_regs->bp, bx, r12-15 not saved */
+
+ orl $TS_COMPAT, ASM_THREAD_INFO(TI_status, %rsp, SIZEOF_PTREGS)
+ testl $_TIF_WORK_SYSCALL_ENTRY, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
+ jnz ia32_tracesys
+
+ia32_do_call:
+ /* 32-bit syscall -> 64-bit C ABI argument conversion */
+ movl %edi, %r8d /* arg5 */
+ movl %ebp, %r9d /* arg6 */
+ xchg %ecx, %esi /* rsi:arg2, rcx:arg4 */
+ movl %ebx, %edi /* arg1 */
+ movl %edx, %edx /* arg3 (zero extension) */
+ cmpq $(IA32_NR_syscalls-1), %rax
+ ja 1f
+
+ call *ia32_sys_call_table(, %rax, 8) /* RIP relative */
+
+ia32_sysret:
+ movq %rax, RAX(%rsp)
+1:
+ jmp int_ret_from_sys_call
+
+ia32_tracesys:
+ SAVE_EXTRA_REGS
+ movq %rsp, %rdi /* &pt_regs -> arg1 */
+ call syscall_trace_enter
+ /*
+ * Reload arg registers from stack in case ptrace changed them.
+ * Don't reload %eax because syscall_trace_enter() returned
+ * the %rax value we should see. But do truncate it to 32 bits.
+ * If it's -1 to make us punt the syscall, then (u32)-1 is still
+ * an appropriately invalid value.
+ */
+ movl RCX(%rsp), %ecx
+ movl RDX(%rsp), %edx
+ movl RSI(%rsp), %esi
+ movl RDI(%rsp), %edi
+ movl %eax, %eax /* zero extension */
+ RESTORE_EXTRA_REGS
+ jmp ia32_do_call
+END(ia32_syscall)
+
+ .macro PTREGSCALL label, func
+ ALIGN
+GLOBAL(\label)
+ leaq \func(%rip), %rax
+ jmp ia32_ptregs_common
+ .endm
+
+ PTREGSCALL stub32_rt_sigreturn, sys32_rt_sigreturn
+ PTREGSCALL stub32_sigreturn, sys32_sigreturn
+ PTREGSCALL stub32_fork, sys_fork
+ PTREGSCALL stub32_vfork, sys_vfork
+
+ ALIGN
+GLOBAL(stub32_clone)
+ leaq sys_clone(%rip), %rax
+ /*
+ * The 32-bit clone ABI is: clone(..., int tls_val, int *child_tidptr).
+ * The 64-bit clone ABI is: clone(..., int *child_tidptr, int tls_val).
+ *
+ * The native 64-bit kernel's sys_clone() implements the latter,
+ * so we need to swap arguments here before calling it:
+ */
+ xchg %r8, %rcx
+ jmp ia32_ptregs_common
+
+ ALIGN
+ia32_ptregs_common:
+ SAVE_EXTRA_REGS 8
+ call *%rax
+ RESTORE_EXTRA_REGS 8
+ ret
+END(ia32_ptregs_common)
+++ /dev/null
-/*
- * Compatibility mode system call entry point for x86-64.
- *
- * Copyright 2000-2002 Andi Kleen, SuSE Labs.
- */
-#include "calling.h"
-#include <asm/asm-offsets.h>
-#include <asm/current.h>
-#include <asm/errno.h>
-#include <asm/ia32_unistd.h>
-#include <asm/thread_info.h>
-#include <asm/segment.h>
-#include <asm/irqflags.h>
-#include <asm/asm.h>
-#include <asm/smap.h>
-#include <linux/linkage.h>
-#include <linux/err.h>
-
-/* Avoid __ASSEMBLER__'ifying <linux/audit.h> just for this. */
-#include <linux/elf-em.h>
-#define AUDIT_ARCH_I386 (EM_386|__AUDIT_ARCH_LE)
-#define __AUDIT_ARCH_LE 0x40000000
-
-#ifndef CONFIG_AUDITSYSCALL
-# define sysexit_audit ia32_ret_from_sys_call
-# define sysretl_audit ia32_ret_from_sys_call
-#endif
-
- .section .entry.text, "ax"
-
-#ifdef CONFIG_PARAVIRT
-ENTRY(native_usergs_sysret32)
- swapgs
- sysretl
-ENDPROC(native_usergs_sysret32)
-#endif
-
-/*
- * 32-bit SYSENTER instruction entry.
- *
- * SYSENTER loads ss, rsp, cs, and rip from previously programmed MSRs.
- * IF and VM in rflags are cleared (IOW: interrupts are off).
- * SYSENTER does not save anything on the stack,
- * and does not save old rip (!!!) and rflags.
- *
- * Arguments:
- * eax system call number
- * ebx arg1
- * ecx arg2
- * edx arg3
- * esi arg4
- * edi arg5
- * ebp user stack
- * 0(%ebp) arg6
- *
- * This is purely a fast path. For anything complicated we use the int 0x80
- * path below. We set up a complete hardware stack frame to share code
- * with the int 0x80 path.
- */
-ENTRY(ia32_sysenter_target)
- /*
- * Interrupts are off on entry.
- * We do not frame this tiny irq-off block with TRACE_IRQS_OFF/ON,
- * it is too small to ever cause noticeable irq latency.
- */
- SWAPGS_UNSAFE_STACK
- movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
- ENABLE_INTERRUPTS(CLBR_NONE)
-
- /* Zero-extending 32-bit regs, do not remove */
- movl %ebp, %ebp
- movl %eax, %eax
-
- movl ASM_THREAD_INFO(TI_sysenter_return, %rsp, 0), %r10d
-
- /* Construct struct pt_regs on stack */
- pushq $__USER32_DS /* pt_regs->ss */
- pushq %rbp /* pt_regs->sp */
- pushfq /* pt_regs->flags */
- pushq $__USER32_CS /* pt_regs->cs */
- pushq %r10 /* pt_regs->ip = thread_info->sysenter_return */
- pushq %rax /* pt_regs->orig_ax */
- pushq %rdi /* pt_regs->di */
- pushq %rsi /* pt_regs->si */
- pushq %rdx /* pt_regs->dx */
- pushq %rcx /* pt_regs->cx */
- pushq $-ENOSYS /* pt_regs->ax */
- cld
- sub $(10*8), %rsp /* pt_regs->r8-11, bp, bx, r12-15 not saved */
-
- /*
- * no need to do an access_ok check here because rbp has been
- * 32-bit zero extended
- */
- ASM_STAC
-1: movl (%rbp), %ebp
- _ASM_EXTABLE(1b, ia32_badarg)
- ASM_CLAC
-
- /*
- * Sysenter doesn't filter flags, so we need to clear NT
- * ourselves. To save a few cycles, we can check whether
- * NT was set instead of doing an unconditional popfq.
- */
- testl $X86_EFLAGS_NT, EFLAGS(%rsp)
- jnz sysenter_fix_flags
-sysenter_flags_fixed:
-
- orl $TS_COMPAT, ASM_THREAD_INFO(TI_status, %rsp, SIZEOF_PTREGS)
- testl $_TIF_WORK_SYSCALL_ENTRY, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
- jnz sysenter_tracesys
-
-sysenter_do_call:
- /* 32-bit syscall -> 64-bit C ABI argument conversion */
- movl %edi, %r8d /* arg5 */
- movl %ebp, %r9d /* arg6 */
- xchg %ecx, %esi /* rsi:arg2, rcx:arg4 */
- movl %ebx, %edi /* arg1 */
- movl %edx, %edx /* arg3 (zero extension) */
-sysenter_dispatch:
- cmpq $(IA32_NR_syscalls-1), %rax
- ja 1f
- call *ia32_sys_call_table(, %rax, 8)
- movq %rax, RAX(%rsp)
-1:
- DISABLE_INTERRUPTS(CLBR_NONE)
- TRACE_IRQS_OFF
- testl $_TIF_ALLWORK_MASK, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
- jnz sysexit_audit
-sysexit_from_sys_call:
- /*
- * NB: SYSEXIT is not obviously safe for 64-bit kernels -- an
- * NMI between STI and SYSEXIT has poorly specified behavior,
- * and and NMI followed by an IRQ with usergs is fatal. So
- * we just pretend we're using SYSEXIT but we really use
- * SYSRETL instead.
- *
- * This code path is still called 'sysexit' because it pairs
- * with 'sysenter' and it uses the SYSENTER calling convention.
- */
- andl $~TS_COMPAT, ASM_THREAD_INFO(TI_status, %rsp, SIZEOF_PTREGS)
- movl RIP(%rsp), %ecx /* User %eip */
- RESTORE_RSI_RDI
- xorl %edx, %edx /* Do not leak kernel information */
- xorq %r8, %r8
- xorq %r9, %r9
- xorq %r10, %r10
- movl EFLAGS(%rsp), %r11d /* User eflags */
- TRACE_IRQS_ON
-
- /*
- * SYSRETL works even on Intel CPUs. Use it in preference to SYSEXIT,
- * since it avoids a dicey window with interrupts enabled.
- */
- movl RSP(%rsp), %esp
-
- /*
- * USERGS_SYSRET32 does:
- * gsbase = user's gs base
- * eip = ecx
- * rflags = r11
- * cs = __USER32_CS
- * ss = __USER_DS
- *
- * The prologue set RIP(%rsp) to VDSO32_SYSENTER_RETURN, which does:
- *
- * pop %ebp
- * pop %edx
- * pop %ecx
- *
- * Therefore, we invoke SYSRETL with EDX and R8-R10 zeroed to
- * avoid info leaks. R11 ends up with VDSO32_SYSENTER_RETURN's
- * address (already known to user code), and R12-R15 are
- * callee-saved and therefore don't contain any interesting
- * kernel data.
- */
- USERGS_SYSRET32
-
-#ifdef CONFIG_AUDITSYSCALL
- .macro auditsys_entry_common
- movl %esi, %r8d /* 5th arg: 4th syscall arg */
- movl %ecx, %r9d /* swap with edx */
- movl %edx, %ecx /* 4th arg: 3rd syscall arg */
- movl %r9d, %edx /* 3rd arg: 2nd syscall arg */
- movl %ebx, %esi /* 2nd arg: 1st syscall arg */
- movl %eax, %edi /* 1st arg: syscall number */
- call __audit_syscall_entry
- movl ORIG_RAX(%rsp), %eax /* reload syscall number */
- movl %ebx, %edi /* reload 1st syscall arg */
- movl RCX(%rsp), %esi /* reload 2nd syscall arg */
- movl RDX(%rsp), %edx /* reload 3rd syscall arg */
- movl RSI(%rsp), %ecx /* reload 4th syscall arg */
- movl RDI(%rsp), %r8d /* reload 5th syscall arg */
- .endm
-
- .macro auditsys_exit exit
- testl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT), ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
- jnz ia32_ret_from_sys_call
- TRACE_IRQS_ON
- ENABLE_INTERRUPTS(CLBR_NONE)
- movl %eax, %esi /* second arg, syscall return value */
- cmpl $-MAX_ERRNO, %eax /* is it an error ? */
- jbe 1f
- movslq %eax, %rsi /* if error sign extend to 64 bits */
-1: setbe %al /* 1 if error, 0 if not */
- movzbl %al, %edi /* zero-extend that into %edi */
- call __audit_syscall_exit
- movq RAX(%rsp), %rax /* reload syscall return value */
- movl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT), %edi
- DISABLE_INTERRUPTS(CLBR_NONE)
- TRACE_IRQS_OFF
- testl %edi, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
- jz \exit
- xorl %eax, %eax /* Do not leak kernel information */
- movq %rax, R11(%rsp)
- movq %rax, R10(%rsp)
- movq %rax, R9(%rsp)
- movq %rax, R8(%rsp)
- jmp int_with_check
- .endm
-
-sysenter_auditsys:
- auditsys_entry_common
- movl %ebp, %r9d /* reload 6th syscall arg */
- jmp sysenter_dispatch
-
-sysexit_audit:
- auditsys_exit sysexit_from_sys_call
-#endif
-
-sysenter_fix_flags:
- pushq $(X86_EFLAGS_IF|X86_EFLAGS_FIXED)
- popfq
- jmp sysenter_flags_fixed
-
-sysenter_tracesys:
-#ifdef CONFIG_AUDITSYSCALL
- testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT), ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
- jz sysenter_auditsys
-#endif
- SAVE_EXTRA_REGS
- xorl %eax, %eax /* Do not leak kernel information */
- movq %rax, R11(%rsp)
- movq %rax, R10(%rsp)
- movq %rax, R9(%rsp)
- movq %rax, R8(%rsp)
- movq %rsp, %rdi /* &pt_regs -> arg1 */
- call syscall_trace_enter
-
- /* Reload arg registers from stack. (see sysenter_tracesys) */
- movl RCX(%rsp), %ecx
- movl RDX(%rsp), %edx
- movl RSI(%rsp), %esi
- movl RDI(%rsp), %edi
- movl %eax, %eax /* zero extension */
-
- RESTORE_EXTRA_REGS
- jmp sysenter_do_call
-ENDPROC(ia32_sysenter_target)
-
-/*
- * 32-bit SYSCALL instruction entry.
- *
- * 32-bit SYSCALL saves rip to rcx, clears rflags.RF, then saves rflags to r11,
- * then loads new ss, cs, and rip from previously programmed MSRs.
- * rflags gets masked by a value from another MSR (so CLD and CLAC
- * are not needed). SYSCALL does not save anything on the stack
- * and does not change rsp.
- *
- * Note: rflags saving+masking-with-MSR happens only in Long mode
- * (in legacy 32-bit mode, IF, RF and VM bits are cleared and that's it).
- * Don't get confused: rflags saving+masking depends on Long Mode Active bit
- * (EFER.LMA=1), NOT on bitness of userspace where SYSCALL executes
- * or target CS descriptor's L bit (SYSCALL does not read segment descriptors).
- *
- * Arguments:
- * eax system call number
- * ecx return address
- * ebx arg1
- * ebp arg2 (note: not saved in the stack frame, should not be touched)
- * edx arg3
- * esi arg4
- * edi arg5
- * esp user stack
- * 0(%esp) arg6
- *
- * This is purely a fast path. For anything complicated we use the int 0x80
- * path below. We set up a complete hardware stack frame to share code
- * with the int 0x80 path.
- */
-ENTRY(ia32_cstar_target)
- /*
- * Interrupts are off on entry.
- * We do not frame this tiny irq-off block with TRACE_IRQS_OFF/ON,
- * it is too small to ever cause noticeable irq latency.
- */
- SWAPGS_UNSAFE_STACK
- movl %esp, %r8d
- movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
- ENABLE_INTERRUPTS(CLBR_NONE)
-
- /* Zero-extending 32-bit regs, do not remove */
- movl %eax, %eax
-
- /* Construct struct pt_regs on stack */
- pushq $__USER32_DS /* pt_regs->ss */
- pushq %r8 /* pt_regs->sp */
- pushq %r11 /* pt_regs->flags */
- pushq $__USER32_CS /* pt_regs->cs */
- pushq %rcx /* pt_regs->ip */
- pushq %rax /* pt_regs->orig_ax */
- pushq %rdi /* pt_regs->di */
- pushq %rsi /* pt_regs->si */
- pushq %rdx /* pt_regs->dx */
- pushq %rbp /* pt_regs->cx */
- movl %ebp, %ecx
- pushq $-ENOSYS /* pt_regs->ax */
- sub $(10*8), %rsp /* pt_regs->r8-11, bp, bx, r12-15 not saved */
-
- /*
- * No need to do an access_ok check here because r8 has been
- * 32-bit zero extended:
- */
- ASM_STAC
-1: movl (%r8), %ebp
- _ASM_EXTABLE(1b, ia32_badarg)
- ASM_CLAC
- orl $TS_COMPAT, ASM_THREAD_INFO(TI_status, %rsp, SIZEOF_PTREGS)
- testl $_TIF_WORK_SYSCALL_ENTRY, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
- jnz cstar_tracesys
-
-cstar_do_call:
- /* 32-bit syscall -> 64-bit C ABI argument conversion */
- movl %edi, %r8d /* arg5 */
- movl %ebp, %r9d /* arg6 */
- xchg %ecx, %esi /* rsi:arg2, rcx:arg4 */
- movl %ebx, %edi /* arg1 */
- movl %edx, %edx /* arg3 (zero extension) */
-
-cstar_dispatch:
- cmpq $(IA32_NR_syscalls-1), %rax
- ja 1f
-
- call *ia32_sys_call_table(, %rax, 8)
- movq %rax, RAX(%rsp)
-1:
- DISABLE_INTERRUPTS(CLBR_NONE)
- TRACE_IRQS_OFF
- testl $_TIF_ALLWORK_MASK, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
- jnz sysretl_audit
-
-sysretl_from_sys_call:
- andl $~TS_COMPAT, ASM_THREAD_INFO(TI_status, %rsp, SIZEOF_PTREGS)
- movl RCX(%rsp), %ebp
- RESTORE_RSI_RDI_RDX
- movl RIP(%rsp), %ecx
- movl EFLAGS(%rsp), %r11d
- xorq %r10, %r10
- xorq %r9, %r9
- xorq %r8, %r8
- TRACE_IRQS_ON
- movl RSP(%rsp), %esp
- /*
- * 64-bit->32-bit SYSRET restores eip from ecx,
- * eflags from r11 (but RF and VM bits are forced to 0),
- * cs and ss are loaded from MSRs.
- * (Note: 32-bit->32-bit SYSRET is different: since r11
- * does not exist, it merely sets eflags.IF=1).
- *
- * NB: On AMD CPUs with the X86_BUG_SYSRET_SS_ATTRS bug, the ss
- * descriptor is not reinitialized. This means that we must
- * avoid SYSRET with SS == NULL, which could happen if we schedule,
- * exit the kernel, and re-enter using an interrupt vector. (All
- * interrupt entries on x86_64 set SS to NULL.) We prevent that
- * from happening by reloading SS in __switch_to.
- */
- USERGS_SYSRET32
-
-#ifdef CONFIG_AUDITSYSCALL
-cstar_auditsys:
- auditsys_entry_common
- movl %ebp, %r9d /* reload 6th syscall arg */
- jmp cstar_dispatch
-
-sysretl_audit:
- auditsys_exit sysretl_from_sys_call
-#endif
-
-cstar_tracesys:
-#ifdef CONFIG_AUDITSYSCALL
- testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT), ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
- jz cstar_auditsys
-#endif
- SAVE_EXTRA_REGS
- xorl %eax, %eax /* Do not leak kernel information */
- movq %rax, R11(%rsp)
- movq %rax, R10(%rsp)
- movq %rax, R9(%rsp)
- movq %rax, R8(%rsp)
- movq %rsp, %rdi /* &pt_regs -> arg1 */
- call syscall_trace_enter
-
- /* Reload arg registers from stack. (see sysenter_tracesys) */
- movl RCX(%rsp), %ecx
- movl RDX(%rsp), %edx
- movl RSI(%rsp), %esi
- movl RDI(%rsp), %edi
- movl %eax, %eax /* zero extension */
-
- RESTORE_EXTRA_REGS
- jmp cstar_do_call
-END(ia32_cstar_target)
-
-ia32_badarg:
- ASM_CLAC
- movq $-EFAULT, %rax
- jmp ia32_sysret
-
-ia32_ret_from_sys_call:
- xorl %eax, %eax /* Do not leak kernel information */
- movq %rax, R11(%rsp)
- movq %rax, R10(%rsp)
- movq %rax, R9(%rsp)
- movq %rax, R8(%rsp)
- jmp int_ret_from_sys_call
-
-/*
- * Emulated IA32 system calls via int 0x80.
- *
- * Arguments:
- * eax system call number
- * ebx arg1
- * ecx arg2
- * edx arg3
- * esi arg4
- * edi arg5
- * ebp arg6 (note: not saved in the stack frame, should not be touched)
- *
- * Notes:
- * Uses the same stack frame as the x86-64 version.
- * All registers except eax must be saved (but ptrace may violate that).
- * Arguments are zero extended. For system calls that want sign extension and
- * take long arguments a wrapper is needed. Most calls can just be called
- * directly.
- * Assumes it is only called from user space and entered with interrupts off.
- */
-
-ENTRY(ia32_syscall)
- /*
- * Interrupts are off on entry.
- * We do not frame this tiny irq-off block with TRACE_IRQS_OFF/ON,
- * it is too small to ever cause noticeable irq latency.
- */
- PARAVIRT_ADJUST_EXCEPTION_FRAME
- SWAPGS
- ENABLE_INTERRUPTS(CLBR_NONE)
-
- /* Zero-extending 32-bit regs, do not remove */
- movl %eax, %eax
-
- /* Construct struct pt_regs on stack (iret frame is already on stack) */
- pushq %rax /* pt_regs->orig_ax */
- pushq %rdi /* pt_regs->di */
- pushq %rsi /* pt_regs->si */
- pushq %rdx /* pt_regs->dx */
- pushq %rcx /* pt_regs->cx */
- pushq $-ENOSYS /* pt_regs->ax */
- pushq $0 /* pt_regs->r8 */
- pushq $0 /* pt_regs->r9 */
- pushq $0 /* pt_regs->r10 */
- pushq $0 /* pt_regs->r11 */
- cld
- sub $(6*8), %rsp /* pt_regs->bp, bx, r12-15 not saved */
-
- orl $TS_COMPAT, ASM_THREAD_INFO(TI_status, %rsp, SIZEOF_PTREGS)
- testl $_TIF_WORK_SYSCALL_ENTRY, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
- jnz ia32_tracesys
-
-ia32_do_call:
- /* 32-bit syscall -> 64-bit C ABI argument conversion */
- movl %edi, %r8d /* arg5 */
- movl %ebp, %r9d /* arg6 */
- xchg %ecx, %esi /* rsi:arg2, rcx:arg4 */
- movl %ebx, %edi /* arg1 */
- movl %edx, %edx /* arg3 (zero extension) */
- cmpq $(IA32_NR_syscalls-1), %rax
- ja 1f
-
- call *ia32_sys_call_table(, %rax, 8) /* RIP relative */
-
-ia32_sysret:
- movq %rax, RAX(%rsp)
-1:
- jmp int_ret_from_sys_call
-
-ia32_tracesys:
- SAVE_EXTRA_REGS
- movq %rsp, %rdi /* &pt_regs -> arg1 */
- call syscall_trace_enter
- /*
- * Reload arg registers from stack in case ptrace changed them.
- * Don't reload %eax because syscall_trace_enter() returned
- * the %rax value we should see. But do truncate it to 32 bits.
- * If it's -1 to make us punt the syscall, then (u32)-1 is still
- * an appropriately invalid value.
- */
- movl RCX(%rsp), %ecx
- movl RDX(%rsp), %edx
- movl RSI(%rsp), %esi
- movl RDI(%rsp), %edi
- movl %eax, %eax /* zero extension */
- RESTORE_EXTRA_REGS
- jmp ia32_do_call
-END(ia32_syscall)
-
- .macro PTREGSCALL label, func
- ALIGN
-GLOBAL(\label)
- leaq \func(%rip), %rax
- jmp ia32_ptregs_common
- .endm
-
- PTREGSCALL stub32_rt_sigreturn, sys32_rt_sigreturn
- PTREGSCALL stub32_sigreturn, sys32_sigreturn
- PTREGSCALL stub32_fork, sys_fork
- PTREGSCALL stub32_vfork, sys_vfork
-
- ALIGN
-GLOBAL(stub32_clone)
- leaq sys_clone(%rip), %rax
- /*
- * The 32-bit clone ABI is: clone(..., int tls_val, int *child_tidptr).
- * The 64-bit clone ABI is: clone(..., int *child_tidptr, int tls_val).
- *
- * The native 64-bit kernel's sys_clone() implements the latter,
- * so we need to swap arguments here before calling it:
- */
- xchg %r8, %rcx
- jmp ia32_ptregs_common
-
- ALIGN
-ia32_ptregs_common:
- SAVE_EXTRA_REGS 8
- call *%rax
- RESTORE_EXTRA_REGS 8
- ret
-END(ia32_ptregs_common)
projects / linux-2.6-block.git / commitdiff