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27 March 2024, 02:37:15 UTC
Revision f56029410a13cae3652d1f34788045c40a13ffc7 authored by Anton Blanchard on 28 May 2014, 22:15:38 UTC, committed by Benjamin Herrenschmidt on 11 July 2014, 03:50:47 UTC 
powerpc/perf: Never program book3s PMCs with values >= 0x80000000
 
We are seeing a lot of PMU warnings on POWER8:

    Can't find PMC that caused IRQ

Looking closer, the active PMC is 0 at this point and we took a PMU
exception on the transition from negative to 0. Some versions of POWER8
have an issue where they edge detect and not level detect PMC overflows.

A number of places program the PMC with (0x80000000 - period_left),
where period_left can be negative. We can either fix all of these or
just ensure that period_left is always >= 1.

This patch takes the second option.

Cc: <stable@vger.kernel.org>
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
1 parent fb43e84
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Tip revision: f56029410a13cae3652d1f34788045c40a13ffc7 authored by Anton Blanchard on 28 May 2014, 22:15:38 UTC
powerpc/perf: Never program book3s PMCs with values >= 0x80000000
Tip revision: f560294
do_mounts.h 
#include <linux/kernel.h>
#include <linux/blkdev.h>
#include <linux/init.h>
#include <linux/syscalls.h>
#include <linux/unistd.h>
#include <linux/slab.h>
#include <linux/mount.h>
#include <linux/major.h>
#include <linux/root_dev.h>

void  change_floppy(char *fmt, ...);
void  mount_block_root(char *name, int flags);
void  mount_root(void);
extern int root_mountflags;

static inline int create_dev(char *name, dev_t dev)
{
	sys_unlink(name);
	return sys_mknod(name, S_IFBLK|0600, new_encode_dev(dev));
}

#if BITS_PER_LONG == 32
static inline u32 bstat(char *name)
{
	struct stat64 stat;
	if (sys_stat64(name, &stat) != 0)
		return 0;
	if (!S_ISBLK(stat.st_mode))
		return 0;
	if (stat.st_rdev != (u32)stat.st_rdev)
		return 0;
	return stat.st_rdev;
}
#else
static inline u32 bstat(char *name)
{
	struct stat stat;
	if (sys_newstat(name, &stat) != 0)
		return 0;
	if (!S_ISBLK(stat.st_mode))
		return 0;
	return stat.st_rdev;
}
#endif

#ifdef CONFIG_BLK_DEV_RAM

int __init rd_load_disk(int n);
int __init rd_load_image(char *from);

#else

static inline int rd_load_disk(int n) { return 0; }
static inline int rd_load_image(char *from) { return 0; }

#endif

#ifdef CONFIG_BLK_DEV_INITRD

int __init initrd_load(void);

#else

static inline int initrd_load(void) { return 0; }

#endif

#ifdef CONFIG_BLK_DEV_MD

void md_run_setup(void);

#else

static inline void md_run_setup(void) {}

#endif
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