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OpenCloudOS-Kernel
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s390: enable HAVE_ARCH_STACKLEAK 

Add support for the stackleak feature. Whenever the kernel returns to user
space the kernel stack is filled with a poison value.

Enabling this feature is quite expensive: e.g. after instrumenting the
getpid() system call function to have a 4kb stack the result is an
increased runtime of the system call by a factor of 3.

Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
This commit is contained in:
Heiko Carstens 2023-03-27 11:37:28 +02:00 committed by Vasily Gorbik
parent 22ca1e7738
commit b94c0ebb1e
2 changed files with 11 additions and 0 deletions
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1
arch/s390/Kconfig
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@ -155,6 +155,7 @@ config S390
select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
select HAVE_ARCH_SECCOMP_FILTER
select HAVE_ARCH_SOFT_DIRTY
select HAVE_ARCH_STACKLEAK
select HAVE_ARCH_TRACEHOOK
select HAVE_ARCH_TRANSPARENT_HUGEPAGE
select HAVE_ARCH_VMAP_STACK

10
arch/s390/kernel/entry.S
View File

@ -150,6 +150,12 @@ _LPP_OFFSET = __LC_LPP
.endm
#endif
.macro STACKLEAK_ERASE
#ifdef CONFIG_GCC_PLUGIN_STACKLEAK
brasl %r14,stackleak_erase_on_task_stack
#endif
.endm
GEN_BR_THUNK %r14
.section .kprobes.text, "ax"
@ -300,6 +306,7 @@ ENTRY(system_call)
MBEAR %r2
lgr %r3,%r14
brasl %r14,__do_syscall
STACKLEAK_ERASE
lctlg %c1,%c1,__LC_USER_ASCE
mvc __LC_RETURN_PSW(16),STACK_FRAME_OVERHEAD+__PT_PSW(%r15)
BPON
@ -315,6 +322,7 @@ ENDPROC(system_call)
ENTRY(ret_from_fork)
lgr %r3,%r11
brasl %r14,__ret_from_fork
STACKLEAK_ERASE
lctlg %c1,%c1,__LC_USER_ASCE
mvc __LC_RETURN_PSW(16),STACK_FRAME_OVERHEAD+__PT_PSW(%r15)
BPON
@ -375,6 +383,7 @@ ENTRY(pgm_check_handler)
brasl %r14,__do_pgm_check
tmhh %r8,0x0001 # returning to user space?
jno .Lpgm_exit_kernel
STACKLEAK_ERASE
lctlg %c1,%c1,__LC_USER_ASCE
BPON
stpt __LC_EXIT_TIMER
@ -440,6 +449,7 @@ ENTRY(\name)
mvc __LC_RETURN_PSW(16),__PT_PSW(%r11)
tmhh %r8,0x0001 # returning to user ?
jno 2f
STACKLEAK_ERASE
lctlg %c1,%c1,__LC_USER_ASCE
BPON
stpt __LC_EXIT_TIMER