mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2025-01-15 00:06:17 +07:00
7bceec4e58
Revise and add CFI CFA and register rule annotations to the vDSO functions for proper stack unwinding and debugging. Because glibc might call the vDSO in special ways, the vDSO code does not rely on a stack frame created by the caller. The TOD clock value can be therefore not stored in the pre-allocated stack area and additional stack space is required. To correctly annotate these situations with CFI, the .cfi_val_offset directive is required to create relative offsets on the value of the stack register %r15. Because the .cfi_val_offset directive is available with recent GNU assembler versions only, additional checks are necessary. Note that if the vDSO is assembled with an older assembler version, stack unwinding and debugging from within the vDSO code might not be possible. Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
163 lines
4.2 KiB
ArmAsm
163 lines
4.2 KiB
ArmAsm
/* SPDX-License-Identifier: GPL-2.0 */
|
|
/*
|
|
* Userland implementation of clock_gettime() for 64 bits processes in a
|
|
* s390 kernel for use in the vDSO
|
|
*
|
|
* Copyright IBM Corp. 2008
|
|
* Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
|
|
*/
|
|
#include <asm/vdso.h>
|
|
#include <asm/asm-offsets.h>
|
|
#include <asm/unistd.h>
|
|
#include <asm/dwarf.h>
|
|
|
|
.text
|
|
.align 4
|
|
.globl __kernel_clock_gettime
|
|
.type __kernel_clock_gettime,@function
|
|
__kernel_clock_gettime:
|
|
CFI_STARTPROC
|
|
aghi %r15,-16
|
|
CFI_DEF_CFA_OFFSET 176
|
|
CFI_VAL_OFFSET 15, -160
|
|
larl %r5,_vdso_data
|
|
cghi %r2,__CLOCK_REALTIME_COARSE
|
|
je 4f
|
|
cghi %r2,__CLOCK_REALTIME
|
|
je 5f
|
|
cghi %r2,-3 /* Per-thread CPUCLOCK with PID=0, VIRT=1 */
|
|
je 9f
|
|
cghi %r2,__CLOCK_MONOTONIC_COARSE
|
|
je 3f
|
|
cghi %r2,__CLOCK_MONOTONIC
|
|
jne 12f
|
|
|
|
/* CLOCK_MONOTONIC */
|
|
0: lg %r4,__VDSO_UPD_COUNT(%r5) /* load update counter */
|
|
tmll %r4,0x0001 /* pending update ? loop */
|
|
jnz 0b
|
|
stcke 0(%r15) /* Store TOD clock */
|
|
lgf %r2,__VDSO_TK_SHIFT(%r5) /* Timekeeper shift */
|
|
lg %r0,__VDSO_WTOM_SEC(%r5)
|
|
lg %r1,1(%r15)
|
|
sg %r1,__VDSO_XTIME_STAMP(%r5) /* TOD - cycle_last */
|
|
msgf %r1,__VDSO_TK_MULT(%r5) /* * tk->mult */
|
|
alg %r1,__VDSO_WTOM_NSEC(%r5)
|
|
srlg %r1,%r1,0(%r2) /* >> tk->shift */
|
|
clg %r4,__VDSO_UPD_COUNT(%r5) /* check update counter */
|
|
jne 0b
|
|
larl %r5,13f
|
|
1: clg %r1,0(%r5)
|
|
jl 2f
|
|
slg %r1,0(%r5)
|
|
aghi %r0,1
|
|
j 1b
|
|
2: stg %r0,0(%r3) /* store tp->tv_sec */
|
|
stg %r1,8(%r3) /* store tp->tv_nsec */
|
|
lghi %r2,0
|
|
aghi %r15,16
|
|
CFI_DEF_CFA_OFFSET 160
|
|
CFI_RESTORE 15
|
|
br %r14
|
|
|
|
/* CLOCK_MONOTONIC_COARSE */
|
|
CFI_DEF_CFA_OFFSET 176
|
|
CFI_VAL_OFFSET 15, -160
|
|
3: lg %r4,__VDSO_UPD_COUNT(%r5) /* load update counter */
|
|
tmll %r4,0x0001 /* pending update ? loop */
|
|
jnz 3b
|
|
lg %r0,__VDSO_WTOM_CRS_SEC(%r5)
|
|
lg %r1,__VDSO_WTOM_CRS_NSEC(%r5)
|
|
clg %r4,__VDSO_UPD_COUNT(%r5) /* check update counter */
|
|
jne 3b
|
|
j 2b
|
|
|
|
/* CLOCK_REALTIME_COARSE */
|
|
4: lg %r4,__VDSO_UPD_COUNT(%r5) /* load update counter */
|
|
tmll %r4,0x0001 /* pending update ? loop */
|
|
jnz 4b
|
|
lg %r0,__VDSO_XTIME_CRS_SEC(%r5)
|
|
lg %r1,__VDSO_XTIME_CRS_NSEC(%r5)
|
|
clg %r4,__VDSO_UPD_COUNT(%r5) /* check update counter */
|
|
jne 4b
|
|
j 7f
|
|
|
|
/* CLOCK_REALTIME */
|
|
5: lg %r4,__VDSO_UPD_COUNT(%r5) /* load update counter */
|
|
tmll %r4,0x0001 /* pending update ? loop */
|
|
jnz 5b
|
|
stcke 0(%r15) /* Store TOD clock */
|
|
lg %r1,1(%r15)
|
|
lg %r0,__VDSO_TS_END(%r5) /* TOD steering end time */
|
|
slgr %r0,%r1 /* now - ts_steering_end */
|
|
ltgr %r0,%r0 /* past end of steering ? */
|
|
jm 17f
|
|
srlg %r0,%r0,15 /* 1 per 2^16 */
|
|
tm __VDSO_TS_DIR+3(%r5),0x01 /* steering direction? */
|
|
jz 18f
|
|
lcgr %r0,%r0 /* negative TOD offset */
|
|
18: algr %r1,%r0 /* add steering offset */
|
|
17: lgf %r2,__VDSO_TK_SHIFT(%r5) /* Timekeeper shift */
|
|
sg %r1,__VDSO_XTIME_STAMP(%r5) /* TOD - cycle_last */
|
|
msgf %r1,__VDSO_TK_MULT(%r5) /* * tk->mult */
|
|
alg %r1,__VDSO_XTIME_NSEC(%r5) /* + tk->xtime_nsec */
|
|
srlg %r1,%r1,0(%r2) /* >> tk->shift */
|
|
lg %r0,__VDSO_XTIME_SEC(%r5) /* tk->xtime_sec */
|
|
clg %r4,__VDSO_UPD_COUNT(%r5) /* check update counter */
|
|
jne 5b
|
|
larl %r5,13f
|
|
6: clg %r1,0(%r5)
|
|
jl 7f
|
|
slg %r1,0(%r5)
|
|
aghi %r0,1
|
|
j 6b
|
|
7: stg %r0,0(%r3) /* store tp->tv_sec */
|
|
stg %r1,8(%r3) /* store tp->tv_nsec */
|
|
lghi %r2,0
|
|
aghi %r15,16
|
|
CFI_DEF_CFA_OFFSET 160
|
|
CFI_RESTORE 15
|
|
br %r14
|
|
|
|
/* CPUCLOCK_VIRT for this thread */
|
|
CFI_DEF_CFA_OFFSET 176
|
|
CFI_VAL_OFFSET 15, -160
|
|
9: lghi %r4,0
|
|
icm %r0,15,__VDSO_ECTG_OK(%r5)
|
|
jz 12f
|
|
sacf 256 /* Magic ectg instruction */
|
|
.insn ssf,0xc80100000000,__VDSO_ECTG_BASE(4),__VDSO_ECTG_USER(4),4
|
|
sacf 0
|
|
algr %r1,%r0 /* r1 = cputime as TOD value */
|
|
mghi %r1,1000 /* convert to nanoseconds */
|
|
srlg %r1,%r1,12 /* r1 = cputime in nanosec */
|
|
lgr %r4,%r1
|
|
larl %r5,13f
|
|
srlg %r1,%r1,9 /* divide by 1000000000 */
|
|
mlg %r0,8(%r5)
|
|
srlg %r0,%r0,11 /* r0 = tv_sec */
|
|
stg %r0,0(%r3)
|
|
msg %r0,0(%r5) /* calculate tv_nsec */
|
|
slgr %r4,%r0 /* r4 = tv_nsec */
|
|
stg %r4,8(%r3)
|
|
lghi %r2,0
|
|
aghi %r15,16
|
|
CFI_DEF_CFA_OFFSET 160
|
|
CFI_RESTORE 15
|
|
br %r14
|
|
|
|
/* Fallback to system call */
|
|
CFI_DEF_CFA_OFFSET 176
|
|
CFI_VAL_OFFSET 15, -160
|
|
12: lghi %r1,__NR_clock_gettime
|
|
svc 0
|
|
aghi %r15,16
|
|
CFI_DEF_CFA_OFFSET 160
|
|
CFI_RESTORE 15
|
|
br %r14
|
|
CFI_ENDPROC
|
|
|
|
13: .quad 1000000000
|
|
14: .quad 19342813113834067
|
|
.size __kernel_clock_gettime,.-__kernel_clock_gettime
|