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Subject[PATCH] x86: mpx: move bd_addr to mm_context_t
Date
Currently bd_addr lives in mm_struct, which is otherwise architecture
independent. Architecture-specific data is supposed to live within
mm_context_t (itself contained in mm_struct).

Other x86-specific context like the pkey accounting data lives in
mm_context_t, and there's no readon the MPX data can't also live there.
So as to keep the arch-specific data togather, and to set a good example
for others, this patch moves bd_addr into x86's mm_context_t.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
---
arch/x86/include/asm/mmu.h | 4 ++++
arch/x86/include/asm/mpx.h | 4 ++--
arch/x86/mm/mpx.c | 10 +++++-----
include/linux/mm_types.h | 4 ----
4 files changed, 11 insertions(+), 11 deletions(-)

I spotted this while trying to find a place to but some arm64-specific data.
I now know to use mm_context_t, but was almost lead astray by the MPX example.

I've given this a build-test (with CONFIG_X86_INTEL_MPX selected), and all
seems happy.

Mark.

diff --git a/arch/x86/include/asm/mmu.h b/arch/x86/include/asm/mmu.h
index 72198c6..f9813b6 100644
--- a/arch/x86/include/asm/mmu.h
+++ b/arch/x86/include/asm/mmu.h
@@ -31,6 +31,10 @@
u16 pkey_allocation_map;
s16 execute_only_pkey;
#endif
+#ifdef CONFIG_X86_INTEL_MPX
+ /* address of the bounds directory */
+ void __user *bd_addr;
+#endif
} mm_context_t;

#ifdef CONFIG_SMP
diff --git a/arch/x86/include/asm/mpx.h b/arch/x86/include/asm/mpx.h
index 7a35495..0b416d4 100644
--- a/arch/x86/include/asm/mpx.h
+++ b/arch/x86/include/asm/mpx.h
@@ -59,7 +59,7 @@
int mpx_handle_bd_fault(void);
static inline int kernel_managing_mpx_tables(struct mm_struct *mm)
{
- return (mm->bd_addr != MPX_INVALID_BOUNDS_DIR);
+ return (mm->context.bd_addr != MPX_INVALID_BOUNDS_DIR);
}
static inline void mpx_mm_init(struct mm_struct *mm)
{
@@ -67,7 +67,7 @@ static inline void mpx_mm_init(struct mm_struct *mm)
* NULL is theoretically a valid place to put the bounds
* directory, so point this at an invalid address.
*/
- mm->bd_addr = MPX_INVALID_BOUNDS_DIR;
+ mm->context.bd_addr = MPX_INVALID_BOUNDS_DIR;
}
void mpx_notify_unmap(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long start, unsigned long end);
diff --git a/arch/x86/mm/mpx.c b/arch/x86/mm/mpx.c
index e4f8009..324e571 100644
--- a/arch/x86/mm/mpx.c
+++ b/arch/x86/mm/mpx.c
@@ -350,12 +350,12 @@ int mpx_enable_management(void)
* The copy_xregs_to_kernel() beneath get_xsave_field_ptr() is
* expected to be relatively expensive. Storing the bounds
* directory here means that we do not have to do xsave in the
- * unmap path; we can just use mm->bd_addr instead.
+ * unmap path; we can just use mm->context.bd_addr instead.
*/
bd_base = mpx_get_bounds_dir();
down_write(&mm->mmap_sem);
- mm->bd_addr = bd_base;
- if (mm->bd_addr == MPX_INVALID_BOUNDS_DIR)
+ mm->context.bd_addr = bd_base;
+ if (mm->context.bd_addr == MPX_INVALID_BOUNDS_DIR)
ret = -ENXIO;

up_write(&mm->mmap_sem);
@@ -370,7 +370,7 @@ int mpx_disable_management(void)
return -ENXIO;

down_write(&mm->mmap_sem);
- mm->bd_addr = MPX_INVALID_BOUNDS_DIR;
+ mm->context.bd_addr = MPX_INVALID_BOUNDS_DIR;
up_write(&mm->mmap_sem);
return 0;
}
@@ -947,7 +947,7 @@ static int try_unmap_single_bt(struct mm_struct *mm,
end = bta_end_vaddr;
}

- bde_vaddr = mm->bd_addr + mpx_get_bd_entry_offset(mm, start);
+ bde_vaddr = mm->context.bd_addr + mpx_get_bd_entry_offset(mm, start);
ret = get_bt_addr(mm, bde_vaddr, &bt_addr);
/*
* No bounds table there, so nothing to unmap.
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 4a8aced..ce70ceb 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -508,10 +508,6 @@ struct mm_struct {
bool tlb_flush_pending;
#endif
struct uprobes_state uprobes_state;
-#ifdef CONFIG_X86_INTEL_MPX
- /* address of the bounds directory */
- void __user *bd_addr;
-#endif
#ifdef CONFIG_HUGETLB_PAGE
atomic_long_t hugetlb_usage;
#endif
--
1.9.1
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