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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2016-01-20 14:01:31 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2016-01-20 14:01:31 -0300
commitb4b7ff4b08e691656c9d77c758fc355833128ac0 (patch)
tree82fcb00e6b918026dc9f2d1f05ed8eee83874cc0 /arch/x86/entry/vdso/vdso32
parent35acfa0fc609f2a2cd95cef4a6a9c3a5c38f1778 (diff)
Linux-libre 4.4-gnupck-4.4-gnu
Diffstat (limited to 'arch/x86/entry/vdso/vdso32')
-rw-r--r--arch/x86/entry/vdso/vdso32/int80.S56
-rw-r--r--arch/x86/entry/vdso/vdso32/syscall.S75
-rw-r--r--arch/x86/entry/vdso/vdso32/sysenter.S116
-rw-r--r--arch/x86/entry/vdso/vdso32/system_call.S89
-rw-r--r--arch/x86/entry/vdso/vdso32/vclock_gettime.c2
5 files changed, 91 insertions, 247 deletions
diff --git a/arch/x86/entry/vdso/vdso32/int80.S b/arch/x86/entry/vdso/vdso32/int80.S
deleted file mode 100644
index b15b7c01a..000000000
--- a/arch/x86/entry/vdso/vdso32/int80.S
+++ /dev/null
@@ -1,56 +0,0 @@
-/*
- * Code for the vDSO. This version uses the old int $0x80 method.
- *
- * First get the common code for the sigreturn entry points.
- * This must come first.
- */
-#include "sigreturn.S"
-
- .text
- .globl __kernel_vsyscall
- .type __kernel_vsyscall,@function
- ALIGN
-__kernel_vsyscall:
-.LSTART_vsyscall:
- int $0x80
- ret
-.LEND_vsyscall:
- .size __kernel_vsyscall,.-.LSTART_vsyscall
- .previous
-
- .section .eh_frame,"a",@progbits
-.LSTARTFRAMEDLSI:
- .long .LENDCIEDLSI-.LSTARTCIEDLSI
-.LSTARTCIEDLSI:
- .long 0 /* CIE ID */
- .byte 1 /* Version number */
- .string "zR" /* NUL-terminated augmentation string */
- .uleb128 1 /* Code alignment factor */
- .sleb128 -4 /* Data alignment factor */
- .byte 8 /* Return address register column */
- .uleb128 1 /* Augmentation value length */
- .byte 0x1b /* DW_EH_PE_pcrel|DW_EH_PE_sdata4. */
- .byte 0x0c /* DW_CFA_def_cfa */
- .uleb128 4
- .uleb128 4
- .byte 0x88 /* DW_CFA_offset, column 0x8 */
- .uleb128 1
- .align 4
-.LENDCIEDLSI:
- .long .LENDFDEDLSI-.LSTARTFDEDLSI /* Length FDE */
-.LSTARTFDEDLSI:
- .long .LSTARTFDEDLSI-.LSTARTFRAMEDLSI /* CIE pointer */
- .long .LSTART_vsyscall-. /* PC-relative start address */
- .long .LEND_vsyscall-.LSTART_vsyscall
- .uleb128 0
- .align 4
-.LENDFDEDLSI:
- .previous
-
- /*
- * Pad out the segment to match the size of the sysenter.S version.
- */
-VDSO32_vsyscall_eh_frame_size = 0x40
- .section .data,"aw",@progbits
- .space VDSO32_vsyscall_eh_frame_size-(.LENDFDEDLSI-.LSTARTFRAMEDLSI), 0
- .previous
diff --git a/arch/x86/entry/vdso/vdso32/syscall.S b/arch/x86/entry/vdso/vdso32/syscall.S
deleted file mode 100644
index 6b286bb52..000000000
--- a/arch/x86/entry/vdso/vdso32/syscall.S
+++ /dev/null
@@ -1,75 +0,0 @@
-/*
- * Code for the vDSO. This version uses the syscall instruction.
- *
- * First get the common code for the sigreturn entry points.
- * This must come first.
- */
-#define SYSCALL_ENTER_KERNEL syscall
-#include "sigreturn.S"
-
-#include <asm/segment.h>
-
- .text
- .globl __kernel_vsyscall
- .type __kernel_vsyscall,@function
- ALIGN
-__kernel_vsyscall:
-.LSTART_vsyscall:
- push %ebp
-.Lpush_ebp:
- movl %ecx, %ebp
- syscall
- movl %ebp, %ecx
- popl %ebp
-.Lpop_ebp:
- ret
-.LEND_vsyscall:
- .size __kernel_vsyscall,.-.LSTART_vsyscall
-
- .section .eh_frame,"a",@progbits
-.LSTARTFRAME:
- .long .LENDCIE-.LSTARTCIE
-.LSTARTCIE:
- .long 0 /* CIE ID */
- .byte 1 /* Version number */
- .string "zR" /* NUL-terminated augmentation string */
- .uleb128 1 /* Code alignment factor */
- .sleb128 -4 /* Data alignment factor */
- .byte 8 /* Return address register column */
- .uleb128 1 /* Augmentation value length */
- .byte 0x1b /* DW_EH_PE_pcrel|DW_EH_PE_sdata4. */
- .byte 0x0c /* DW_CFA_def_cfa */
- .uleb128 4
- .uleb128 4
- .byte 0x88 /* DW_CFA_offset, column 0x8 */
- .uleb128 1
- .align 4
-.LENDCIE:
-
- .long .LENDFDE1-.LSTARTFDE1 /* Length FDE */
-.LSTARTFDE1:
- .long .LSTARTFDE1-.LSTARTFRAME /* CIE pointer */
- .long .LSTART_vsyscall-. /* PC-relative start address */
- .long .LEND_vsyscall-.LSTART_vsyscall
- .uleb128 0 /* Augmentation length */
- /* What follows are the instructions for the table generation.
- We have to record all changes of the stack pointer. */
- .byte 0x40 + .Lpush_ebp-.LSTART_vsyscall /* DW_CFA_advance_loc */
- .byte 0x0e /* DW_CFA_def_cfa_offset */
- .uleb128 8
- .byte 0x85, 0x02 /* DW_CFA_offset %ebp -8 */
- .byte 0x40 + .Lpop_ebp-.Lpush_ebp /* DW_CFA_advance_loc */
- .byte 0xc5 /* DW_CFA_restore %ebp */
- .byte 0x0e /* DW_CFA_def_cfa_offset */
- .uleb128 4
- .align 4
-.LENDFDE1:
- .previous
-
- /*
- * Pad out the segment to match the size of the sysenter.S version.
- */
-VDSO32_vsyscall_eh_frame_size = 0x40
- .section .data,"aw",@progbits
- .space VDSO32_vsyscall_eh_frame_size-(.LENDFDE1-.LSTARTFRAME), 0
- .previous
diff --git a/arch/x86/entry/vdso/vdso32/sysenter.S b/arch/x86/entry/vdso/vdso32/sysenter.S
deleted file mode 100644
index e354bceee..000000000
--- a/arch/x86/entry/vdso/vdso32/sysenter.S
+++ /dev/null
@@ -1,116 +0,0 @@
-/*
- * Code for the vDSO. This version uses the sysenter instruction.
- *
- * First get the common code for the sigreturn entry points.
- * This must come first.
- */
-#include "sigreturn.S"
-
-/*
- * The caller puts arg2 in %ecx, which gets pushed. The kernel will use
- * %ecx itself for arg2. The pushing is because the sysexit instruction
- * (found in entry.S) requires that we clobber %ecx with the desired %esp.
- * User code might expect that %ecx is unclobbered though, as it would be
- * for returning via the iret instruction, so we must push and pop.
- *
- * The caller puts arg3 in %edx, which the sysexit instruction requires
- * for %eip. Thus, exactly as for arg2, we must push and pop.
- *
- * Arg6 is different. The caller puts arg6 in %ebp. Since the sysenter
- * instruction clobbers %esp, the user's %esp won't even survive entry
- * into the kernel. We store %esp in %ebp. Code in entry.S must fetch
- * arg6 from the stack.
- *
- * You can not use this vsyscall for the clone() syscall because the
- * three words on the parent stack do not get copied to the child.
- */
- .text
- .globl __kernel_vsyscall
- .type __kernel_vsyscall,@function
- ALIGN
-__kernel_vsyscall:
-.LSTART_vsyscall:
- push %ecx
-.Lpush_ecx:
- push %edx
-.Lpush_edx:
- push %ebp
-.Lenter_kernel:
- movl %esp,%ebp
- sysenter
-
- /* 7: align return point with nop's to make disassembly easier */
- .space 7,0x90
-
- /* 14: System call restart point is here! (SYSENTER_RETURN-2) */
- int $0x80
- /* 16: System call normal return point is here! */
-VDSO32_SYSENTER_RETURN: /* Symbol used by sysenter.c via vdso32-syms.h */
- pop %ebp
-.Lpop_ebp:
- pop %edx
-.Lpop_edx:
- pop %ecx
-.Lpop_ecx:
- ret
-.LEND_vsyscall:
- .size __kernel_vsyscall,.-.LSTART_vsyscall
- .previous
-
- .section .eh_frame,"a",@progbits
-.LSTARTFRAMEDLSI:
- .long .LENDCIEDLSI-.LSTARTCIEDLSI
-.LSTARTCIEDLSI:
- .long 0 /* CIE ID */
- .byte 1 /* Version number */
- .string "zR" /* NUL-terminated augmentation string */
- .uleb128 1 /* Code alignment factor */
- .sleb128 -4 /* Data alignment factor */
- .byte 8 /* Return address register column */
- .uleb128 1 /* Augmentation value length */
- .byte 0x1b /* DW_EH_PE_pcrel|DW_EH_PE_sdata4. */
- .byte 0x0c /* DW_CFA_def_cfa */
- .uleb128 4
- .uleb128 4
- .byte 0x88 /* DW_CFA_offset, column 0x8 */
- .uleb128 1
- .align 4
-.LENDCIEDLSI:
- .long .LENDFDEDLSI-.LSTARTFDEDLSI /* Length FDE */
-.LSTARTFDEDLSI:
- .long .LSTARTFDEDLSI-.LSTARTFRAMEDLSI /* CIE pointer */
- .long .LSTART_vsyscall-. /* PC-relative start address */
- .long .LEND_vsyscall-.LSTART_vsyscall
- .uleb128 0
- /* What follows are the instructions for the table generation.
- We have to record all changes of the stack pointer. */
- .byte 0x40 + (.Lpush_ecx-.LSTART_vsyscall) /* DW_CFA_advance_loc */
- .byte 0x0e /* DW_CFA_def_cfa_offset */
- .byte 0x08 /* RA at offset 8 now */
- .byte 0x40 + (.Lpush_edx-.Lpush_ecx) /* DW_CFA_advance_loc */
- .byte 0x0e /* DW_CFA_def_cfa_offset */
- .byte 0x0c /* RA at offset 12 now */
- .byte 0x40 + (.Lenter_kernel-.Lpush_edx) /* DW_CFA_advance_loc */
- .byte 0x0e /* DW_CFA_def_cfa_offset */
- .byte 0x10 /* RA at offset 16 now */
- .byte 0x85, 0x04 /* DW_CFA_offset %ebp -16 */
- /* Finally the epilogue. */
- .byte 0x40 + (.Lpop_ebp-.Lenter_kernel) /* DW_CFA_advance_loc */
- .byte 0x0e /* DW_CFA_def_cfa_offset */
- .byte 0x0c /* RA at offset 12 now */
- .byte 0xc5 /* DW_CFA_restore %ebp */
- .byte 0x40 + (.Lpop_edx-.Lpop_ebp) /* DW_CFA_advance_loc */
- .byte 0x0e /* DW_CFA_def_cfa_offset */
- .byte 0x08 /* RA at offset 8 now */
- .byte 0x40 + (.Lpop_ecx-.Lpop_edx) /* DW_CFA_advance_loc */
- .byte 0x0e /* DW_CFA_def_cfa_offset */
- .byte 0x04 /* RA at offset 4 now */
- .align 4
-.LENDFDEDLSI:
- .previous
-
- /*
- * Emit a symbol with the size of this .eh_frame data,
- * to verify it matches the other versions.
- */
-VDSO32_vsyscall_eh_frame_size = (.LENDFDEDLSI-.LSTARTFRAMEDLSI)
diff --git a/arch/x86/entry/vdso/vdso32/system_call.S b/arch/x86/entry/vdso/vdso32/system_call.S
new file mode 100644
index 000000000..3a1d92970
--- /dev/null
+++ b/arch/x86/entry/vdso/vdso32/system_call.S
@@ -0,0 +1,89 @@
+/*
+ * AT_SYSINFO entry point
+*/
+
+#include <asm/dwarf2.h>
+#include <asm/cpufeature.h>
+#include <asm/alternative-asm.h>
+
+/*
+ * First get the common code for the sigreturn entry points.
+ * This must come first.
+ */
+#include "sigreturn.S"
+
+ .text
+ .globl __kernel_vsyscall
+ .type __kernel_vsyscall,@function
+ ALIGN
+__kernel_vsyscall:
+ CFI_STARTPROC
+ /*
+ * Reshuffle regs so that all of any of the entry instructions
+ * will preserve enough state.
+ *
+ * A really nice entry sequence would be:
+ * pushl %edx
+ * pushl %ecx
+ * movl %esp, %ecx
+ *
+ * Unfortunately, naughty Android versions between July and December
+ * 2015 actually hardcode the traditional Linux SYSENTER entry
+ * sequence. That is severely broken for a number of reasons (ask
+ * anyone with an AMD CPU, for example). Nonetheless, we try to keep
+ * it working approximately as well as it ever worked.
+ *
+ * This link may eludicate some of the history:
+ * https://android-review.googlesource.com/#/q/Iac3295376d61ef83e713ac9b528f3b50aa780cd7
+ * personally, I find it hard to understand what's going on there.
+ *
+ * Note to future user developers: DO NOT USE SYSENTER IN YOUR CODE.
+ * Execute an indirect call to the address in the AT_SYSINFO auxv
+ * entry. That is the ONLY correct way to make a fast 32-bit system
+ * call on Linux. (Open-coding int $0x80 is also fine, but it's
+ * slow.)
+ */
+ pushl %ecx
+ CFI_ADJUST_CFA_OFFSET 4
+ CFI_REL_OFFSET ecx, 0
+ pushl %edx
+ CFI_ADJUST_CFA_OFFSET 4
+ CFI_REL_OFFSET edx, 0
+ pushl %ebp
+ CFI_ADJUST_CFA_OFFSET 4
+ CFI_REL_OFFSET ebp, 0
+
+ #define SYSENTER_SEQUENCE "movl %esp, %ebp; sysenter"
+ #define SYSCALL_SEQUENCE "movl %ecx, %ebp; syscall"
+
+#ifdef CONFIG_X86_64
+ /* If SYSENTER (Intel) or SYSCALL32 (AMD) is available, use it. */
+ ALTERNATIVE_2 "", SYSENTER_SEQUENCE, X86_FEATURE_SYSENTER32, \
+ SYSCALL_SEQUENCE, X86_FEATURE_SYSCALL32
+#else
+ ALTERNATIVE "", SYSENTER_SEQUENCE, X86_FEATURE_SEP
+#endif
+
+ /* Enter using int $0x80 */
+ int $0x80
+GLOBAL(int80_landing_pad)
+
+ /*
+ * Restore EDX and ECX in case they were clobbered. EBP is not
+ * clobbered (the kernel restores it), but it's cleaner and
+ * probably faster to pop it than to adjust ESP using addl.
+ */
+ popl %ebp
+ CFI_RESTORE ebp
+ CFI_ADJUST_CFA_OFFSET -4
+ popl %edx
+ CFI_RESTORE edx
+ CFI_ADJUST_CFA_OFFSET -4
+ popl %ecx
+ CFI_RESTORE ecx
+ CFI_ADJUST_CFA_OFFSET -4
+ ret
+ CFI_ENDPROC
+
+ .size __kernel_vsyscall,.-__kernel_vsyscall
+ .previous
diff --git a/arch/x86/entry/vdso/vdso32/vclock_gettime.c b/arch/x86/entry/vdso/vdso32/vclock_gettime.c
index 175cc72c0..87a86e017 100644
--- a/arch/x86/entry/vdso/vdso32/vclock_gettime.c
+++ b/arch/x86/entry/vdso/vdso32/vclock_gettime.c
@@ -14,11 +14,13 @@
*/
#undef CONFIG_64BIT
#undef CONFIG_X86_64
+#undef CONFIG_PGTABLE_LEVELS
#undef CONFIG_ILLEGAL_POINTER_VALUE
#undef CONFIG_SPARSEMEM_VMEMMAP
#undef CONFIG_NR_CPUS
#define CONFIG_X86_32 1
+#define CONFIG_PGTABLE_LEVELS 2
#define CONFIG_PAGE_OFFSET 0
#define CONFIG_ILLEGAL_POINTER_VALUE 0
#define CONFIG_NR_CPUS 1