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>

diff --git a/arch/s390/include/asm/sclp.h b/arch/s390/include/asm/sclp.h
index 3cae9168f63c4f5070fd659ee93ab0c82b6a26a4..e44a8d7959f513ebbd2982314369a5706bda3528 100644 (file)
--- a/arch/s390/include/asm/sclp.h
+++ b/arch/s390/include/asm/sclp.h
@@ -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);

diff --git a/arch/s390/kernel/early_printk.c b/arch/s390/kernel/early_printk.c
index 9431784d7796b57cd16604795ea35c8b8f8c235e..40c1dfec944e6040c3f1402679f318250190ffb4 100644 (file)
--- a/arch/s390/kernel/early_printk.c
+++ b/arch/s390/kernel/early_printk.c
@@ -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 = {

diff --git a/arch/s390/kernel/swsusp.S b/arch/s390/kernel/swsusp.S
index a049a7b9d6e893801a1ecd79d9332d3faea8d0ba..c1a080b11ae97743d2553f8e07a99a956ce22763 100644 (file)
--- a/arch/s390/kernel/swsusp.S
+++ b/arch/s390/kernel/swsusp.S
@@ -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:

diff --git a/drivers/s390/char/sclp_early_core.c b/drivers/s390/char/sclp_early_core.c
index eceba3858cefbbe0b2ce46df46751f4d53bc7122..2f61f5579aa54708213f3226c940ef65c462b72b 100644 (file)
--- a/drivers/s390/char/sclp_early_core.c
+++ b/drivers/s390/char/sclp_early_core.c
@@ -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);
 }