Re: [patch] paravirt: isolate module ops

From: Rusty Russell
Date: Sat Jan 06 2007 - 12:47:10 EST

On Sat, 2007-01-06 at 08:08 +0100, Ingo Molnar wrote:
> btw., your patch does not apply to current -git - could you please
> rebase this patch to the head of your queue so that upstream can pick it
> up?

OK, here it is against rc3-git4.

Name: don't export paravirt_ops structure, do individual functions

Wrap the paravirt_ops members we want to export in wrapper functions.
Since we binary-patch the critical ones, this doesn't make a speed
impact.

I moved drm_follow_page into the core, to avoid having to wrap the
various pte ops. Unlining kernel_fpu_end and using that in the RAID6
code would remove the need to export clts/read_cr0/write_cr0 too.

Signed-off-by: Rusty Russell <rusty@xxxxxxxxxxxxxxx>

diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/dontdiff --minimal linux-2.6.20-rc3-git4/arch/i386/kernel/paravirt.c working-2.6.20-rc3-git4/arch/i386/kernel/paravirt.c
--- linux-2.6.20-rc3-git4/arch/i386/kernel/paravirt.c 2007-01-07 03:41:32.000000000 +1100
+++ working-2.6.20-rc3-git4/arch/i386/kernel/paravirt.c 2007-01-07 04:21:59.000000000 +1100
@@ -482,6 +482,123 @@ static int __init print_banner(void)
}
core_initcall(print_banner);

+unsigned long paravirt_save_flags(void)
+{
+ return paravirt_ops.save_fl();
+}
+EXPORT_SYMBOL(paravirt_save_flags);
+
+void paravirt_restore_flags(unsigned long flags)
+{
+ paravirt_ops.restore_fl(flags);
+}
+EXPORT_SYMBOL(paravirt_restore_flags);
+
+void paravirt_irq_disable(void)
+{
+ paravirt_ops.irq_disable();
+}
+EXPORT_SYMBOL(paravirt_irq_disable);
+
+void paravirt_irq_enable(void)
+{
+ paravirt_ops.irq_enable();
+}
+EXPORT_SYMBOL(paravirt_irq_enable);
+
+void paravirt_io_delay(void)
+{
+ paravirt_ops.io_delay();
+}
+EXPORT_SYMBOL(paravirt_io_delay);
+
+void paravirt_const_udelay(unsigned long loops)
+{
+ paravirt_ops.const_udelay(loops);
+}
+EXPORT_SYMBOL(paravirt_const_udelay);
+
+u64 paravirt_read_msr(unsigned int msr, int *err)
+{
+ return paravirt_ops.read_msr(msr, err);
+}
+EXPORT_SYMBOL(paravirt_read_msr);
+
+int paravirt_write_msr(unsigned int msr, u64 val)
+{
+ return paravirt_ops.write_msr(msr, val);
+}
+EXPORT_SYMBOL(paravirt_write_msr);
+
+u64 paravirt_read_tsc(void)
+{
+ return paravirt_ops.read_tsc();
+}
+EXPORT_SYMBOL(paravirt_read_tsc);
+
+int paravirt_enabled(void)
+{
+ return paravirt_ops.paravirt_enabled;
+}
+EXPORT_SYMBOL(paravirt_enabled);
+
+void clts(void)
+{
+ paravirt_ops.clts();
+}
+EXPORT_SYMBOL(clts);
+
+unsigned long read_cr0(void)
+{
+ return paravirt_ops.read_cr0();
+}
+EXPORT_SYMBOL_GPL(read_cr0);
+
+void write_cr0(unsigned long cr0)
+{
+ paravirt_ops.write_cr0(cr0);
+}
+EXPORT_SYMBOL_GPL(write_cr0);
+
+void wbinvd(void)
+{
+ paravirt_ops.wbinvd();
+}
+EXPORT_SYMBOL(wbinvd);
+
+void raw_safe_halt(void)
+{
+ paravirt_ops.safe_halt();
+}
+EXPORT_SYMBOL_GPL(raw_safe_halt);
+
+void halt(void)
+{
+ paravirt_ops.safe_halt();
+}
+EXPORT_SYMBOL_GPL(halt);
+
+#ifdef CONFIG_X86_LOCAL_APIC
+void apic_write(unsigned long reg, unsigned long v)
+{
+ paravirt_ops.apic_write(reg,v);
+}
+EXPORT_SYMBOL_GPL(apic_write);
+
+unsigned long apic_read(unsigned long reg)
+{
+ return paravirt_ops.apic_read(reg);
+}
+EXPORT_SYMBOL_GPL(apic_read);
+#endif
+
+void __cpuid(unsigned int *eax, unsigned int *ebx,
+ unsigned int *ecx, unsigned int *edx)
+{
+ paravirt_ops.cpuid(eax, ebx, ecx, edx);
+}
+EXPORT_SYMBOL(__cpuid);
+
/* We simply declare start_kernel to be the paravirt probe of last resort. */
paravirt_probe(start_kernel);

@@ -566,4 +683,3 @@ struct paravirt_ops paravirt_ops = {
.irq_enable_sysexit = native_irq_enable_sysexit,
.iret = native_iret,
};
-EXPORT_SYMBOL(paravirt_ops);
diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/dontdiff --minimal linux-2.6.20-rc3-git4/drivers/char/drm/drm_memory.h working-2.6.20-rc3-git4/drivers/char/drm/drm_memory.h
--- linux-2.6.20-rc3-git4/drivers/char/drm/drm_memory.h 2006-09-22 15:36:13.000000000 +1000
+++ working-2.6.20-rc3-git4/drivers/char/drm/drm_memory.h 2007-01-07 04:19:07.000000000 +1100
@@ -58,11 +58,7 @@

static inline unsigned long drm_follow_page(void *vaddr)
{
- pgd_t *pgd = pgd_offset_k((unsigned long)vaddr);
- pud_t *pud = pud_offset(pgd, (unsigned long)vaddr);
- pmd_t *pmd = pmd_offset(pud, (unsigned long)vaddr);
- pte_t *ptep = pte_offset_kernel(pmd, (unsigned long)vaddr);
- return pte_pfn(*ptep) << PAGE_SHIFT;
+ return __follow_page(vaddr);
}

#else /* __OS_HAS_AGP */
diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/dontdiff --minimal linux-2.6.20-rc3-git4/include/asm-i386/delay.h working-2.6.20-rc3-git4/include/asm-i386/delay.h
--- linux-2.6.20-rc3-git4/include/asm-i386/delay.h 2007-01-07 03:42:32.000000000 +1100
+++ working-2.6.20-rc3-git4/include/asm-i386/delay.h 2007-01-07 04:08:46.000000000 +1100
@@ -17,9 +17,9 @@ extern void __const_udelay(unsigned long
extern void __delay(unsigned long loops);

#if defined(CONFIG_PARAVIRT) && !defined(USE_REAL_TIME_DELAY)
-#define udelay(n) paravirt_ops.const_udelay((n) * 0x10c7ul)
+#define udelay(n) paravirt_const_udelay((n) * 0x10c7ul)

-#define ndelay(n) paravirt_ops.const_udelay((n) * 5ul)
+#define ndelay(n) paravirt_const_udelay((n) * 5ul)

#else /* !PARAVIRT || USE_REAL_TIME_DELAY */

diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/dontdiff --minimal linux-2.6.20-rc3-git4/include/asm-i386/paravirt.h working-2.6.20-rc3-git4/include/asm-i386/paravirt.h
--- linux-2.6.20-rc3-git4/include/asm-i386/paravirt.h 2007-01-07 03:42:33.000000000 +1100
+++ working-2.6.20-rc3-git4/include/asm-i386/paravirt.h 2007-01-07 04:13:44.000000000 +1100
@@ -152,8 +152,6 @@ struct paravirt_ops

extern struct paravirt_ops paravirt_ops;

-#define paravirt_enabled() (paravirt_ops.paravirt_enabled)
-
static inline void load_esp0(struct tss_struct *tss,
struct thread_struct *thread)
{
@@ -177,11 +175,8 @@ static inline void do_time_init(void)
}

/* The paravirtualized CPUID instruction. */
-static inline void __cpuid(unsigned int *eax, unsigned int *ebx,
- unsigned int *ecx, unsigned int *edx)
-{
- paravirt_ops.cpuid(eax, ebx, ecx, edx);
-}
+void __cpuid(unsigned int *eax, unsigned int *ebx,
+ unsigned int *ecx, unsigned int *edx);

/*
* These special macros can be used to get or set a debugging register
@@ -189,11 +184,6 @@ static inline void __cpuid(unsigned int
#define get_debugreg(var, reg) var = paravirt_ops.get_debugreg(reg)
#define set_debugreg(val, reg) paravirt_ops.set_debugreg(reg, val)

-#define clts() paravirt_ops.clts()
-
-#define read_cr0() paravirt_ops.read_cr0()
-#define write_cr0(x) paravirt_ops.write_cr0(x)
-
#define read_cr2() paravirt_ops.read_cr2()
#define write_cr2(x) paravirt_ops.write_cr2(x)

@@ -204,62 +194,51 @@ static inline void __cpuid(unsigned int
#define read_cr4_safe(x) paravirt_ops.read_cr4_safe()
#define write_cr4(x) paravirt_ops.write_cr4(x)

-static inline void raw_safe_halt(void)
-{
- paravirt_ops.safe_halt();
-}
-
-static inline void halt(void)
-{
- paravirt_ops.safe_halt();
-}
-#define wbinvd() paravirt_ops.wbinvd()
-
#define get_kernel_rpl() (paravirt_ops.kernel_rpl)

#define rdmsr(msr,val1,val2) do { \
int _err; \
- u64 _l = paravirt_ops.read_msr(msr,&_err); \
+ u64 _l = paravirt_read_msr(msr,&_err); \
val1 = (u32)_l; \
val2 = _l >> 32; \
} while(0)

#define wrmsr(msr,val1,val2) do { \
u64 _l = ((u64)(val2) << 32) | (val1); \
- paravirt_ops.write_msr((msr), _l); \
+ paravirt_write_msr((msr), _l); \
} while(0)

#define rdmsrl(msr,val) do { \
int _err; \
- val = paravirt_ops.read_msr((msr),&_err); \
+ val = paravirt_read_msr((msr),&_err); \
} while(0)

-#define wrmsrl(msr,val) (paravirt_ops.write_msr((msr),(val)))
+#define wrmsrl(msr,val) (paravirt_write_msr((msr),(val)))
#define wrmsr_safe(msr,a,b) ({ \
u64 _l = ((u64)(b) << 32) | (a); \
- paravirt_ops.write_msr((msr),_l); \
+ paravirt_write_msr((msr),_l); \
})

/* rdmsr with exception handling */
#define rdmsr_safe(msr,a,b) ({ \
int _err; \
- u64 _l = paravirt_ops.read_msr(msr,&_err); \
+ u64 _l = paravirt_read_msr(msr,&_err); \
(*a) = (u32)_l; \
(*b) = _l >> 32; \
_err; })

#define rdtsc(low,high) do { \
- u64 _l = paravirt_ops.read_tsc(); \
+ u64 _l = paravirt_read_tsc(); \
low = (u32)_l; \
high = _l >> 32; \
} while(0)

#define rdtscl(low) do { \
- u64 _l = paravirt_ops.read_tsc(); \
+ u64 _l = paravirt_read_tsc(); \
low = (int)_l; \
} while(0)

-#define rdtscll(val) (val = paravirt_ops.read_tsc())
+#define rdtscll(val) (val = paravirt_read_tsc())

#define write_tsc(val1,val2) wrmsr(0x10, val1, val2)

@@ -345,6 +324,26 @@ static inline void pte_update_defer(stru
paravirt_ops.pte_update_defer(mm, addr, ptep);
}

+/* These are the functions exported to modules. */
+int paravirt_enabled(void);
+unsigned long paravirt_save_flags(void);
+void paravirt_restore_flags(unsigned long flags);
+void paravirt_irq_disable(void);
+void paravirt_irq_enable(void);
+void paravirt_const_udelay(unsigned long loops);
+void paravirt_io_delay(void);
+u64 paravirt_read_msr(unsigned int msr, int *err);
+int paravirt_write_msr(unsigned int msr, u64 val);
+u64 paravirt_read_tsc(void);
+void raw_safe_halt(void);
+void halt(void);
+void wbinvd(void);
+
+/* These will be unexported once raid6 is fixed... */
+void clts(void);
+unsigned long read_cr0(void);
+void write_cr0(unsigned long);
+
#ifdef CONFIG_X86_PAE
static inline void set_pte_atomic(pte_t *ptep, pte_t pteval)
{
@@ -394,42 +393,38 @@ static inline unsigned long __raw_local_
unsigned long f;

__asm__ __volatile__(paravirt_alt( "pushl %%ecx; pushl %%edx;"
- "call *%1;"
+ "call paravirt_save_flags;"
"popl %%edx; popl %%ecx",
PARAVIRT_SAVE_FLAGS, CLBR_NONE)
- : "=a"(f): "m"(paravirt_ops.save_fl)
- : "memory", "cc");
+ : "=a"(f) : : "memory", "cc");
return f;
}

static inline void raw_local_irq_restore(unsigned long f)
{
__asm__ __volatile__(paravirt_alt( "pushl %%ecx; pushl %%edx;"
- "call *%1;"
+ "call paravirt_restore_flags;"
"popl %%edx; popl %%ecx",
PARAVIRT_RESTORE_FLAGS, CLBR_EAX)
- : "=a"(f) : "m" (paravirt_ops.restore_fl), "0"(f)
- : "memory", "cc");
+ : "=a"(f) : "0"(f) : "memory", "cc");
}

static inline void raw_local_irq_disable(void)
{
__asm__ __volatile__(paravirt_alt( "pushl %%ecx; pushl %%edx;"
- "call *%0;"
+ "call paravirt_irq_disable;"
"popl %%edx; popl %%ecx",
PARAVIRT_IRQ_DISABLE, CLBR_EAX)
- : : "m" (paravirt_ops.irq_disable)
- : "memory", "eax", "cc");
+ : : : "memory", "eax", "cc");
}

static inline void raw_local_irq_enable(void)
{
__asm__ __volatile__(paravirt_alt( "pushl %%ecx; pushl %%edx;"
- "call *%0;"
+ "call paravirt_irq_enable;"
"popl %%edx; popl %%ecx",
PARAVIRT_IRQ_ENABLE, CLBR_EAX)
- : : "m" (paravirt_ops.irq_enable)
- : "memory", "eax", "cc");
+ : : : "memory", "eax", "cc");
}

static inline unsigned long __raw_local_irq_save(void)
@@ -437,15 +432,13 @@ static inline unsigned long __raw_local_
unsigned long f;

__asm__ __volatile__(paravirt_alt( "pushl %%ecx; pushl %%edx;"
- "call *%1; pushl %%eax;"
- "call *%2; popl %%eax;"
- "popl %%edx; popl %%ecx",
+ "call paravirt_save_flags;"
+ "pushl %%eax;"
+ "call paravirt_irq_disable;"
+ "popl %%eax;popl %%edx; popl %%ecx",
PARAVIRT_SAVE_FLAGS_IRQ_DISABLE,
CLBR_NONE)
- : "=a"(f)
- : "m" (paravirt_ops.save_fl),
- "m" (paravirt_ops.irq_disable)
- : "memory", "cc");
+ : "=a"(f) : : "memory", "cc");
return f;
}

diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/dontdiff --minimal linux-2.6.20-rc3-git4/include/linux/irqflags.h working-2.6.20-rc3-git4/include/linux/irqflags.h
--- linux-2.6.20-rc3-git4/include/linux/irqflags.h 2006-09-22 15:37:14.000000000 +1000
+++ working-2.6.20-rc3-git4/include/linux/irqflags.h 2007-01-07 04:08:46.000000000 +1100
@@ -74,11 +74,11 @@
#endif /* CONFIG_TRACE_IRQFLAGS_SUPPORT */

#ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
-#define safe_halt() \
- do { \
- trace_hardirqs_on(); \
- raw_safe_halt(); \
- } while (0)
+static inline void safe_halt(void)
+{
+ trace_hardirqs_on();
+ raw_safe_halt();
+}

#define local_save_flags(flags) raw_local_save_flags(flags)

diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/dontdiff --minimal linux-2.6.20-rc3-git4/include/linux/mm.h working-2.6.20-rc3-git4/include/linux/mm.h
--- linux-2.6.20-rc3-git4/include/linux/mm.h 2007-01-07 03:42:43.000000000 +1100
+++ working-2.6.20-rc3-git4/include/linux/mm.h 2007-01-07 04:20:41.000000000 +1100
@@ -1127,6 +1127,8 @@ struct page *follow_page(struct vm_area_
#define FOLL_GET 0x04 /* do get_page on page */
#define FOLL_ANON 0x08 /* give ZERO_PAGE if no pgtable */

+unsigned long __follow_page(void *vaddr);
+
#ifdef CONFIG_PROC_FS
void vm_stat_account(struct mm_struct *, unsigned long, struct file *, long);
#else
diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/dontdiff --minimal linux-2.6.20-rc3-git4/mm/memory.c working-2.6.20-rc3-git4/mm/memory.c
--- linux-2.6.20-rc3-git4/mm/memory.c 2007-01-07 03:42:49.000000000 +1100
+++ working-2.6.20-rc3-git4/mm/memory.c 2007-01-07 04:19:20.000000000 +1100
@@ -976,6 +976,17 @@ no_page_table:
return page;
}

+/* You don't want to use this function. It's for drm_memory.c. */
+unsigned long __follow_page(void *vaddr)
+{
+ pgd_t *pgd = pgd_offset_k((unsigned long)vaddr);
+ pud_t *pud = pud_offset(pgd, (unsigned long)vaddr);
+ pmd_t *pmd = pmd_offset(pud, (unsigned long)vaddr);
+ pte_t *ptep = pte_offset_kernel(pmd, (unsigned long)vaddr);
+ return pte_pfn(*ptep) << PAGE_SHIFT;
+}
+EXPORT_SYMBOL_GPL(__follow_page);
+
int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
unsigned long start, int len, int write, int force,
struct page **pages, struct vm_area_struct **vmas)


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