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s390/hibernate: fix error handling when suspend cpu != resume cpu 

The resume code checks if the resume cpu is the same as the suspend cpu.
If not, and if it is also not possible to switch to the suspend cpu, an
error message should be printed and the resume process should be stopped
by loading a disabled wait psw.

The current logic is broken in multiple ways, the message is never printed,
and the disabled wait psw never loaded because the kernel panics before that:
- sam31 and SIGP_SET_ARCHITECTURE to ESA mode is wrong, this will break
  on the first 64bit instruction in sclp_early_printk().
- The init stack should be used, but the stack pointer is not set up correctly
  (missing aghi %r15,-STACK_FRAME_OVERHEAD).
- __sclp_early_printk() checks the sclp_init_state. If it is not
  sclp_init_state_uninitialized, it simply returns w/o printing anything.
  In the resumed kernel however, sclp_init_state will never be uninitialized.

This patch fixes those issues by removing the sam31/ESA logic, adding a
correct init stack pointer, and also introducing sclp_early_printk_force()
to allow using sclp_early_printk() even when sclp_init_state is not
uninitialized.

Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Gerald Schaefer 2018-09-10 18:03:29 +02:00 committed by Martin Schwidefsky
parent 4b92e7fd76
commit 55a5542a54
4 changed files with 14 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
arch/s390/include/asm/sclp.h
View File

@ -108,7 +108,8 @@ int sclp_early_get_core_info(struct sclp_core_info *info);
void sclp_early_get_ipl_info(struct sclp_ipl_info *info);
void sclp_early_detect(void);
void sclp_early_printk(const char *s);
void __sclp_early_printk(const char *s, unsigned int len);
void sclp_early_printk_force(const char *s);
void __sclp_early_printk(const char *s, unsigned int len, unsigned int force);
int _sclp_get_core_info(struct sclp_core_info *info);
int sclp_core_configure(u8 core);

2
arch/s390/kernel/early_printk.c
View File

@ -10,7 +10,7 @@
static void sclp_early_write(struct console *con, const char *s, unsigned int len)
{
__sclp_early_printk(s, len);
__sclp_early_printk(s, len, 0);
}
static struct console sclp_early_console = {

8
arch/s390/kernel/swsusp.S
View File

@ -198,12 +198,10 @@ pgm_check_entry:
/* Suspend CPU not available -> panic */
larl %r15,init_thread_union
ahi %r15,1<<(PAGE_SHIFT+THREAD_SIZE_ORDER)
aghi %r15,1<<(PAGE_SHIFT+THREAD_SIZE_ORDER)
aghi %r15,-STACK_FRAME_OVERHEAD
larl %r2,.Lpanic_string
lghi %r1,0
sam31
sigp %r1,%r0,SIGP_SET_ARCHITECTURE
brasl %r14,sclp_early_printk
brasl %r14,sclp_early_printk_force
larl %r3,.Ldisabled_wait_31
lpsw 0(%r3)
4:

11
drivers/s390/char/sclp_early_core.c
View File

@ -210,11 +210,11 @@ static int sclp_early_setup(int disable, int *have_linemode, int *have_vt220)
* Output one or more lines of text on the SCLP console (VT220 and /
* or line-mode).
*/
void __sclp_early_printk(const char *str, unsigned int len)
void __sclp_early_printk(const char *str, unsigned int len, unsigned int force)
{
int have_linemode, have_vt220;
if (sclp_init_state != sclp_init_state_uninitialized)
if (!force && sclp_init_state != sclp_init_state_uninitialized)
return;
if (sclp_early_setup(0, &have_linemode, &have_vt220) != 0)
return;
@ -227,5 +227,10 @@ void __sclp_early_printk(const char *str, unsigned int len)
void sclp_early_printk(const char *str)
{
__sclp_early_printk(str, strlen(str));
__sclp_early_printk(str, strlen(str), 0);
}
void sclp_early_printk_force(const char *str)
{
__sclp_early_printk(str, strlen(str), 1);
}