arch/powerpc/kernel/vdso/sigtramp32.S

Source file repositories/reference/linux-study-clean/arch/powerpc/kernel/vdso/sigtramp32.S

File Facts

System
Linux kernel
Corpus path
arch/powerpc/kernel/vdso/sigtramp32.S
Extension
.S
Size
9496 bytes
Lines
296
Domain
Architecture Layer
Bucket
arch/powerpc
Inferred role
Architecture Layer: arch/powerpc
Status
atlas-only

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

#include <asm/processor.h>
#include <asm/ppc_asm.h>
#include <asm/unistd.h>
#include <asm/vdso.h>

	.text

/* The nop here is a hack.  The dwarf2 unwind routines subtract 1 from
   the return address to get an address in the middle of the presumed
   call instruction.  Since we don't have a call here, we artificially
   extend the range covered by the unwind info by adding a nop before
   the real start.  */
	nop
V_FUNCTION_BEGIN(__kernel_sigtramp32)
.Lsig_start = . - 4
	li	r0,__NR_sigreturn
	sc
.Lsig_end:
V_FUNCTION_END(__kernel_sigtramp32)

.Lsigrt_start:
	nop
V_FUNCTION_BEGIN(__kernel_sigtramp_rt32)
	li	r0,__NR_rt_sigreturn
	sc
.Lsigrt_end:
V_FUNCTION_END(__kernel_sigtramp_rt32)

	.section .eh_frame,"a",@progbits

/* Register r1 can be found at offset 4 of a pt_regs structure.
   A pointer to the pt_regs is stored in memory at the old sp plus PTREGS.  */
#define cfa_save \
  .byte 0x0f;			/* DW_CFA_def_cfa_expression */		\
  .uleb128 9f - 1f;		/*   length */				\
1:									\
  .byte 0x71; .sleb128 PTREGS;	/*     DW_OP_breg1 */			\
  .byte 0x06;			/*     DW_OP_deref */			\
  .byte 0x23; .uleb128 RSIZE;	/*     DW_OP_plus_uconst */		\
  .byte 0x06;			/*     DW_OP_deref */			\
9:

/* Register REGNO can be found at offset OFS of a pt_regs structure.
   A pointer to the pt_regs is stored in memory at the old sp plus PTREGS.  */
#define rsave(regno, ofs) \
  .byte 0x10;			/* DW_CFA_expression */			\
  .uleb128 regno;		/*   regno */				\
  .uleb128 9f - 1f;		/*   length */				\
1:									\
  .byte 0x71; .sleb128 PTREGS;	/*     DW_OP_breg1 */			\
  .byte 0x06;			/*     DW_OP_deref */			\
  .ifne ofs;								\
    .byte 0x23; .uleb128 ofs;	/*     DW_OP_plus_uconst */		\
  .endif;								\
9:

/* If msr bit 1<<25 is set, then VMX register REGNO is at offset REGNO*16
   of the VMX reg struct.  The VMX reg struct is at offset VREGS of
   the pt_regs struct.  This macro is for REGNO == 0, and contains
   'subroutines' that the other macros jump to.  */
#define vsave_msr0(regno) \
  .byte 0x10;			/* DW_CFA_expression */			\
  .uleb128 regno + 77;		/*   regno */				\
  .uleb128 9f - 1f;		/*   length */				\
1:									\
  .byte 0x30 + regno;		/*     DW_OP_lit0 */			\
2:									\
  .byte 0x40;			/*     DW_OP_lit16 */			\
  .byte 0x1e;			/*     DW_OP_mul */			\
3:									\

Annotation

Implementation Notes