From e9f6288aa48d9be64c584bd2117aee85cdb5f78c Mon Sep 17 00:00:00 2001
From: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Date: Thu, 24 May 2012 14:35:16 +0200
Subject: [PATCH] s390/kernel: Introduce memcpy_absolute() function
This patch introduces the new function memcpy_absolute() that allows to
copy memory using absolute addressing. This means that the prefix swap
does not apply when this function is used.
With this patch also all s390 kernel code that accesses absolute zero
now uses the new memcpy_absolute() function. The old and less generic
copy_to_absolute_zero() function is removed.
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---
arch/s390/include/asm/uaccess.h | 2 +-
arch/s390/kernel/ipl.c | 15 +++++++------
arch/s390/kernel/os_info.c | 2 +-
arch/s390/kernel/setup.c | 12 ++++++-----
arch/s390/mm/maccess.c | 38 ++++++++++++++-------------------
5 files changed, 34 insertions(+), 35 deletions(-)
diff --git a/arch/s390/include/asm/uaccess.h b/arch/s390/include/asm/uaccess.h
index 8f2cada4f7c91..8e83da66df0d6 100644
--- a/arch/s390/include/asm/uaccess.h
+++ b/arch/s390/include/asm/uaccess.h
@@ -377,7 +377,7 @@ clear_user(void __user *to, unsigned long n)
}
extern int memcpy_real(void *, void *, size_t);
-extern void copy_to_absolute_zero(void *dest, void *src, size_t count);
+extern void memcpy_absolute(void *, void *, size_t);
extern int copy_to_user_real(void __user *dest, void *src, size_t count);
extern int copy_from_user_real(void *dest, void __user *src, size_t count);
diff --git a/arch/s390/kernel/ipl.c b/arch/s390/kernel/ipl.c
index dcfdcb3ea1637..2f6cfd460cb6a 100644
--- a/arch/s390/kernel/ipl.c
+++ b/arch/s390/kernel/ipl.c
@@ -1528,12 +1528,15 @@ static struct shutdown_action __refdata dump_action = {
static void dump_reipl_run(struct shutdown_trigger *trigger)
{
- u32 csum;
-
- csum = csum_partial(reipl_block_actual, reipl_block_actual->hdr.len, 0);
- copy_to_absolute_zero(&S390_lowcore.ipib_checksum, &csum, sizeof(csum));
- copy_to_absolute_zero(&S390_lowcore.ipib, &reipl_block_actual,
- sizeof(reipl_block_actual));
+ struct {
+ void *addr;
+ __u32 csum;
+ } __packed ipib;
+
+ ipib.csum = csum_partial(reipl_block_actual,
+ reipl_block_actual->hdr.len, 0);
+ ipib.addr = reipl_block_actual;
+ memcpy_absolute(&S390_lowcore.ipib, &ipib, sizeof(ipib));
dump_run(trigger);
}
diff --git a/arch/s390/kernel/os_info.c b/arch/s390/kernel/os_info.c
index f2fe18f3f01fc..95fa5ac6c4ced 100644
--- a/arch/s390/kernel/os_info.c
+++ b/arch/s390/kernel/os_info.c
@@ -60,7 +60,7 @@ void __init os_info_init(void)
os_info.version_minor = OS_INFO_VERSION_MINOR;
os_info.magic = OS_INFO_MAGIC;
os_info.csum = os_info_csum(&os_info);
- copy_to_absolute_zero(&S390_lowcore.os_info, &ptr, sizeof(ptr));
+ memcpy_absolute(&S390_lowcore.os_info, &ptr, sizeof(ptr));
}
#ifdef CONFIG_CRASH_DUMP
diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index 06264ae8ccd9e..489d1d8d96b06 100644
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -428,10 +428,12 @@ static void __init setup_lowcore(void)
lc->restart_fn = (unsigned long) do_restart;
lc->restart_data = 0;
lc->restart_source = -1UL;
- memcpy(&S390_lowcore.restart_stack, &lc->restart_stack,
- 4*sizeof(unsigned long));
- copy_to_absolute_zero(&S390_lowcore.restart_psw,
- &lc->restart_psw, sizeof(psw_t));
+
+ /* Setup absolute zero lowcore */
+ memcpy_absolute(&S390_lowcore.restart_stack, &lc->restart_stack,
+ 4 * sizeof(unsigned long));
+ memcpy_absolute(&S390_lowcore.restart_psw, &lc->restart_psw,
+ sizeof(lc->restart_psw));
set_prefix((u32)(unsigned long) lc);
lowcore_ptr[0] = lc;
@@ -598,7 +600,7 @@ static void __init setup_vmcoreinfo(void)
#ifdef CONFIG_KEXEC
unsigned long ptr = paddr_vmcoreinfo_note();
- copy_to_absolute_zero(&S390_lowcore.vmcore_info, &ptr, sizeof(ptr));
+ memcpy_absolute(&S390_lowcore.vmcore_info, &ptr, sizeof(ptr));
#endif
}
diff --git a/arch/s390/mm/maccess.c b/arch/s390/mm/maccess.c
index 795a0a9bb2eba..921fa541dc043 100644
--- a/arch/s390/mm/maccess.c
+++ b/arch/s390/mm/maccess.c
@@ -101,19 +101,27 @@ int memcpy_real(void *dest, void *src, size_t count)
}
/*
- * Copy memory to absolute zero
+ * Copy memory in absolute mode (kernel to kernel)
*/
-void copy_to_absolute_zero(void *dest, void *src, size_t count)
+void memcpy_absolute(void *dest, void *src, size_t count)
{
- unsigned long cr0;
+ unsigned long cr0, flags, prefix;
- BUG_ON((unsigned long) dest + count >= sizeof(struct _lowcore));
- preempt_disable();
+ flags = arch_local_irq_save();
__ctl_store(cr0, 0, 0);
__ctl_clear_bit(0, 28); /* disable lowcore protection */
- memcpy_real(dest + store_prefix(), src, count);
+ prefix = store_prefix();
+ if (prefix) {
+ local_mcck_disable();
+ set_prefix(0);
+ memcpy(dest, src, count);
+ set_prefix(prefix);
+ local_mcck_enable();
+ } else {
+ memcpy(dest, src, count);
+ }
__ctl_load(cr0, 0, 0);
- preempt_enable();
+ arch_local_irq_restore(flags);
}
/*
@@ -187,20 +195,6 @@ static int is_swapped(unsigned long addr)
return 0;
}
-/*
- * Return swapped prefix or zero page address
- */
-static unsigned long get_swapped(unsigned long addr)
-{
- unsigned long prefix = store_prefix();
-
- if (addr < sizeof(struct _lowcore))
- return addr + prefix;
- if (addr >= prefix && addr < prefix + sizeof(struct _lowcore))
- return addr - prefix;
- return addr;
-}
-
/*
* Convert a physical pointer for /dev/mem access
*
@@ -218,7 +212,7 @@ void *xlate_dev_mem_ptr(unsigned long addr)
size = PAGE_SIZE - (addr & ~PAGE_MASK);
bounce = (void *) __get_free_page(GFP_ATOMIC);
if (bounce)
- memcpy_real(bounce, (void *) get_swapped(addr), size);
+ memcpy_absolute(bounce, (void *) addr, size);
}
preempt_enable();
put_online_cpus();
--
2.39.5