Commit a278e7ea authored by Michael Neuling's avatar Michael Neuling Committed by Michael Ellerman
Browse files

powerpc: Fix compile issue with force DAWR 



If you compile with KVM but without CONFIG_HAVE_HW_BREAKPOINT you fail
at linking with:
  arch/powerpc/kvm/book3s_hv_rmhandlers.o:(.text+0x708): undefined reference to `dawr_force_enable'

This was caused by commit c1fe190c ("powerpc: Add force enable of
DAWR on P9 option").

This moves a bunch of code around to fix this. It moves a lot of the
DAWR code in a new file and creates a new CONFIG_PPC_DAWR to enable
compiling it.

Fixes: c1fe190c ("powerpc: Add force enable of DAWR on P9 option")
Signed-off-by: default avatarMichael Neuling <mikey@neuling.org>
[mpe: Minor formatting in set_dawr()]
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 548c54ac

arch/powerpc/Kconfig

+4 −0
Original line number Diff line number Diff line
@@ -236,6 +236,7 @@ config PPC 
	select OLD_SIGSUSPEND

	select PCI_DOMAINS			if PCI

	select PCI_SYSCALL			if PCI

	select PPC_DAWR				if PPC64

	select RTC_LIB

	select SPARSE_IRQ

	select SYSCTL_EXCEPTION_TRACE
@@ -372,6 +373,9 @@ config PPC_ADV_DEBUG_DAC_RANGE 
	depends on PPC_ADV_DEBUG_REGS && 44x

	default y



config PPC_DAWR

	bool



config ZONE_DMA

	bool

	default y if PPC_BOOK3E_64

arch/powerpc/include/asm/hw_breakpoint.h

+14 −7
Original line number Diff line number Diff line
@@ -90,18 +90,25 @@ static inline void hw_breakpoint_disable(void) 
extern void thread_change_pc(struct task_struct *tsk, struct pt_regs *regs);

int hw_breakpoint_handler(struct die_args *args);



extern int set_dawr(struct arch_hw_breakpoint *brk);

#else	/* CONFIG_HAVE_HW_BREAKPOINT */

static inline void hw_breakpoint_disable(void) { }

static inline void thread_change_pc(struct task_struct *tsk,

					struct pt_regs *regs) { }



#endif	/* CONFIG_HAVE_HW_BREAKPOINT */





#ifdef CONFIG_PPC_DAWR

extern bool dawr_force_enable;

static inline bool dawr_enabled(void)

{

	return dawr_force_enable;

}



#else	/* CONFIG_HAVE_HW_BREAKPOINT */

static inline void hw_breakpoint_disable(void) { }

static inline void thread_change_pc(struct task_struct *tsk,

					struct pt_regs *regs) { }

int set_dawr(struct arch_hw_breakpoint *brk);

#else

static inline bool dawr_enabled(void) { return false; }

#endif	/* CONFIG_HAVE_HW_BREAKPOINT */

static inline int set_dawr(struct arch_hw_breakpoint *brk) { return -1; }

#endif



#endif	/* __KERNEL__ */

#endif	/* _PPC_BOOK3S_64_HW_BREAKPOINT_H */

arch/powerpc/kernel/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -56,6 +56,7 @@ obj-$(CONFIG_PPC64) += setup_64.o sys_ppc32.o \ 
obj-$(CONFIG_VDSO32)		+= vdso32/

obj-$(CONFIG_PPC_WATCHDOG)	+= watchdog.o

obj-$(CONFIG_HAVE_HW_BREAKPOINT)	+= hw_breakpoint.o

obj-$(CONFIG_PPC_DAWR)		+= dawr.o

obj-$(CONFIG_PPC_BOOK3S_64)	+= cpu_setup_ppc970.o cpu_setup_pa6t.o

obj-$(CONFIG_PPC_BOOK3S_64)	+= cpu_setup_power.o

obj-$(CONFIG_PPC_BOOK3S_64)	+= mce.o mce_power.o

arch/powerpc/kernel/dawr.c

0 → 100644
+101 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0+

/*

 * DAWR infrastructure

 *

 * Copyright 2019, Michael Neuling, IBM Corporation.

 */



#include <linux/types.h>

#include <linux/export.h>

#include <linux/fs.h>

#include <linux/debugfs.h>

#include <asm/debugfs.h>

#include <asm/machdep.h>

#include <asm/hvcall.h>



bool dawr_force_enable;

EXPORT_SYMBOL_GPL(dawr_force_enable);



int set_dawr(struct arch_hw_breakpoint *brk)

{

	unsigned long dawr, dawrx, mrd;



	dawr = brk->address;



	dawrx  = (brk->type & (HW_BRK_TYPE_READ | HW_BRK_TYPE_WRITE))

		<< (63 - 58);

	dawrx |= ((brk->type & (HW_BRK_TYPE_TRANSLATE)) >> 2) << (63 - 59);

	dawrx |= (brk->type & (HW_BRK_TYPE_PRIV_ALL)) >> 3;

	/*

	 * DAWR length is stored in field MDR bits 48:53.  Matches range in

	 * doublewords (64 bits) baised by -1 eg. 0b000000=1DW and

	 * 0b111111=64DW.

	 * brk->len is in bytes.

	 * This aligns up to double word size, shifts and does the bias.

	 */

	mrd = ((brk->len + 7) >> 3) - 1;

	dawrx |= (mrd & 0x3f) << (63 - 53);



	if (ppc_md.set_dawr)

		return ppc_md.set_dawr(dawr, dawrx);



	mtspr(SPRN_DAWR, dawr);

	mtspr(SPRN_DAWRX, dawrx);



	return 0;

}



static void set_dawr_cb(void *info)

{

	set_dawr(info);

}



static ssize_t dawr_write_file_bool(struct file *file,

				    const char __user *user_buf,

				    size_t count, loff_t *ppos)

{

	struct arch_hw_breakpoint null_brk = {0, 0, 0};

	size_t rc;



	/* Send error to user if they hypervisor won't allow us to write DAWR */

	if (!dawr_force_enable &&

	    firmware_has_feature(FW_FEATURE_LPAR) &&

	    set_dawr(&null_brk) != H_SUCCESS)

		return -ENODEV;



	rc = debugfs_write_file_bool(file, user_buf, count, ppos);

	if (rc)

		return rc;



	/* If we are clearing, make sure all CPUs have the DAWR cleared */

	if (!dawr_force_enable)

		smp_call_function(set_dawr_cb, &null_brk, 0);



	return rc;

}



static const struct file_operations dawr_enable_fops = {

	.read =		debugfs_read_file_bool,

	.write =	dawr_write_file_bool,

	.open =		simple_open,

	.llseek =	default_llseek,

};



static int __init dawr_force_setup(void)

{

	if (cpu_has_feature(CPU_FTR_DAWR)) {

		/* Don't setup sysfs file for user control on P8 */

		dawr_force_enable = true;

		return 0;

	}



	if (PVR_VER(mfspr(SPRN_PVR)) == PVR_POWER9) {

		/* Turn DAWR off by default, but allow admin to turn it on */

		debugfs_create_file_unsafe("dawr_enable_dangerous", 0600,

					   powerpc_debugfs_root,

					   &dawr_force_enable,

					   &dawr_enable_fops);

	}

	return 0;

}

arch_initcall(dawr_force_setup);

arch/powerpc/kernel/hw_breakpoint.c

+0 −61
Original line number Diff line number Diff line
@@ -380,64 +380,3 @@ void hw_breakpoint_pmu_read(struct perf_event *bp) 
{

	/* TODO */

}
 


bool dawr_force_enable;

EXPORT_SYMBOL_GPL(dawr_force_enable);



static void set_dawr_cb(void *info)

{

	set_dawr(info);

}



static ssize_t dawr_write_file_bool(struct file *file,

				    const char __user *user_buf,

				    size_t count, loff_t *ppos)

{

	struct arch_hw_breakpoint null_brk = {0, 0, 0};

	size_t rc;



	/* Send error to user if they hypervisor won't allow us to write DAWR */

	if ((!dawr_force_enable) &&

	    (firmware_has_feature(FW_FEATURE_LPAR)) &&

	    (set_dawr(&null_brk) != H_SUCCESS))

		return -1;



	rc = debugfs_write_file_bool(file, user_buf, count, ppos);

	if (rc)

		return rc;



	/* If we are clearing, make sure all CPUs have the DAWR cleared */

	if (!dawr_force_enable)

		smp_call_function(set_dawr_cb, &null_brk, 0);



	return rc;

}



static const struct file_operations dawr_enable_fops = {

	.read =		debugfs_read_file_bool,

	.write =	dawr_write_file_bool,

	.open =		simple_open,

	.llseek =	default_llseek,

};



static int __init dawr_force_setup(void)

{

	dawr_force_enable = false;



	if (cpu_has_feature(CPU_FTR_DAWR)) {

		/* Don't setup sysfs file for user control on P8 */

		dawr_force_enable = true;

		return 0;

	}



	if (PVR_VER(mfspr(SPRN_PVR)) == PVR_POWER9) {

		/* Turn DAWR off by default, but allow admin to turn it on */

		dawr_force_enable = false;

		debugfs_create_file_unsafe("dawr_enable_dangerous", 0600,

					   powerpc_debugfs_root,

					   &dawr_force_enable,

					   &dawr_enable_fops);

	}

	return 0;

}

arch_initcall(dawr_force_setup);

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