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Re: [PATCH v2 1/2] include: don't use asm/page.h from common headers

To: Jan Beulich <jbeulich@xxxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxxx>
From: Julien Grall <julien@xxxxxxx>
Date: Wed, 13 Jan 2021 18:47:32 +0000
Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>, George Dunlap <george.dunlap@xxxxxxxxxx>, Ian Jackson <iwj@xxxxxxxxxxxxxx>, Stefano Stabellini <sstabellini@xxxxxxxxxx>, Wei Liu <wl@xxxxxxx>, Hongyan Xia <hx242@xxxxxxx>, Roger Pau Monné <roger.pau@xxxxxxxxxx>, Paul Durrant <paul@xxxxxxx>
Delivery-date: Wed, 13 Jan 2021 18:47:51 +0000
List-id: Xen developer discussion <xen-devel.lists.xenproject.org>

Hi Jan,

On 05/01/2021 12:37, Jan Beulich wrote:

Doing so limits what can be done in (in particular included by) this per-
arch header. Abstract out page shift/size related #define-s, which is all
the respective headers care about. Extend the replacement / removal to
some x86 headers as well; some others now need to include page.h (and
they really should have before).

Arm's VADDR_BITS gets dropped altogether: Its current value is clearly
wrong for 64-bit, but the constant also isn't used anywhere right now.

While Arm used vaddr_t in PAGE_OFFSET(), this use is compatible with
that of unsigned long in the new common implementation.

Also drop the dead PAGE_FLAG_MASK at this occasion.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>


Acked-by: Julien Grall <jgrall@xxxxxxxxxx>

Cheers,

---
v2: Have just a single PAGE_OFFSET(). Rename per-arch headers to
     page-bits.h. Drop VADDR_BITS altogether for Arm.

--- a/xen/arch/arm/arm64/lib/clear_page.S
+++ b/xen/arch/arm/arm64/lib/clear_page.S
@@ -14,6 +14,8 @@
   * along with this program.  If not, see <http://www.gnu.org/licenses/>.
   */

+#include <xen/page-size.h>

+
  /*
   * Clear page @dest
   *
--- a/xen/include/asm-arm/config.h
+++ b/xen/include/asm-arm/config.h
@@ -176,11 +176,6 @@
  #define FIXMAP_ACPI_BEGIN  2  /* Start mappings of ACPI tables */
  #define FIXMAP_ACPI_END    (FIXMAP_ACPI_BEGIN + NUM_FIXMAP_ACPI_PAGES - 1)  
/* End mappings of ACPI tables */

-#define PAGE_SHIFT 12

-#define PAGE_SIZE           (_AC(1,L) << PAGE_SHIFT)
-#define PAGE_MASK           (~(PAGE_SIZE-1))
-#define PAGE_FLAG_MASK      (~0)
-
  #define NR_hypercalls 64

#define STACK_ORDER 3

--- a/xen/include/asm-arm/current.h
+++ b/xen/include/asm-arm/current.h
@@ -1,6 +1,7 @@
  #ifndef __ARM_CURRENT_H__
  #define __ARM_CURRENT_H__

+#include <xen/page-size.h>

  #include <xen/percpu.h>

#include <asm/processor.h>

--- a/xen/include/asm-arm/page.h
+++ b/xen/include/asm-arm/page.h
@@ -2,21 +2,11 @@
  #define __ARM_PAGE_H__

#include <public/xen.h>

+#include <xen/page-size.h>
  #include <asm/processor.h>
  #include <asm/lpae.h>
  #include <asm/sysregs.h>

-#ifdef CONFIG_ARM_64

-#define PADDR_BITS              48
-#else
-#define PADDR_BITS              40
-#endif
-#define PADDR_MASK              ((1ULL << PADDR_BITS)-1)
-#define PAGE_OFFSET(ptr)        ((vaddr_t)(ptr) & ~PAGE_MASK)
-
-#define VADDR_BITS              32
-#define VADDR_MASK              (~0UL)
-
  /* Shareability values for the LPAE entries */
  #define LPAE_SH_NON_SHAREABLE 0x0
  #define LPAE_SH_UNPREDICTALE  0x1
--- /dev/null
+++ b/xen/include/asm-arm/page-bits.h
@@ -0,0 +1,12 @@
+#ifndef __ARM_PAGE_SHIFT_H__
+#define __ARM_PAGE_SHIFT_H__
+
+#define PAGE_SHIFT              12
+
+#ifdef CONFIG_ARM_64
+#define PADDR_BITS              48
+#else
+#define PADDR_BITS              40
+#endif
+
+#endif /* __ARM_PAGE_SHIFT_H__ */
--- a/xen/include/asm-x86/current.h
+++ b/xen/include/asm-x86/current.h
@@ -8,8 +8,8 @@
  #define __X86_CURRENT_H__

#include <xen/percpu.h>

+#include <xen/page-size.h>
  #include <public/xen.h>
-#include <asm/page.h>

/*

   * Xen's cpu stacks are 8 pages (8-page aligned), arranged as:
--- a/xen/include/asm-x86/desc.h
+++ b/xen/include/asm-x86/desc.h
@@ -1,6 +1,8 @@
  #ifndef __ARCH_DESC_H
  #define __ARCH_DESC_H

+#include <asm/page.h>

+
  /*
   * Xen reserves a memory page of GDT entries.
   * No guest GDT entries exist beyond the Xen reserved area.
--- a/xen/include/asm-x86/fixmap.h
+++ b/xen/include/asm-x86/fixmap.h
@@ -12,7 +12,7 @@
  #ifndef _ASM_FIXMAP_H
  #define _ASM_FIXMAP_H

-#include <asm/page.h>

+#include <xen/page-size.h>

#define FIXADDR_TOP (VMAP_VIRT_END - PAGE_SIZE)

  #define FIXADDR_X_TOP (XEN_VIRT_END - PAGE_SIZE)
--- a/xen/include/asm-x86/guest/hyperv-hcall.h
+++ b/xen/include/asm-x86/guest/hyperv-hcall.h
@@ -20,12 +20,12 @@
  #define __X86_HYPERV_HCALL_H__

#include <xen/lib.h>

+#include <xen/page-size.h>
  #include <xen/types.h>

#include <asm/asm_defns.h>

  #include <asm/fixmap.h>
  #include <asm/guest/hyperv-tlfs.h>
-#include <asm/page.h>

static inline uint64_t hv_do_hypercall(uint64_t control, paddr_t input_addr,

                                         paddr_t output_addr)
--- a/xen/include/asm-x86/guest/hyperv-tlfs.h
+++ b/xen/include/asm-x86/guest/hyperv-tlfs.h
@@ -10,8 +10,8 @@
  #define _ASM_X86_HYPERV_TLFS_H

#include <xen/bitops.h>

+#include <xen/page-size.h>
  #include <xen/types.h>
-#include <asm/page.h>

/*

   * While not explicitly listed in the TLFS, Hyper-V always runs with a page 
size
--- a/xen/include/asm-x86/io.h
+++ b/xen/include/asm-x86/io.h
@@ -3,7 +3,6 @@

#include <xen/vmap.h>

  #include <xen/types.h>
-#include <asm/page.h>

#define readb(x) (*(volatile uint8_t *)(x))

  #define readw(x) (*(volatile uint16_t *)(x))
--- a/xen/include/asm-x86/mm.h
+++ b/xen/include/asm-x86/mm.h
@@ -6,6 +6,7 @@
  #include <xen/spinlock.h>
  #include <xen/rwlock.h>
  #include <asm/io.h>
+#include <asm/page.h>
  #include <asm/uaccess.h>
  #include <asm/x86_emulate.h>

--- a/xen/include/asm-x86/page.h

+++ b/xen/include/asm-x86/page.h
@@ -2,15 +2,7 @@
  #define __X86_PAGE_H__

#include <xen/const.h>

-
-/*
- * It is important that the masks are signed quantities. This ensures that
- * the compiler sign-extends a 32-bit mask to 64 bits if that is required.
- */
-#define PAGE_SIZE           (_AC(1,L) << PAGE_SHIFT)
-#define PAGE_MASK           (~(PAGE_SIZE-1))
-#define PAGE_FLAG_MASK      (~0)
-#define PAGE_OFFSET(ptr)    ((unsigned long)(ptr) & ~PAGE_MASK)
+#include <xen/page-size.h>

#define PAGE_ORDER_4K 0

  #define PAGE_ORDER_2M       9
--- /dev/null
+++ b/xen/include/asm-x86/page-bits.h
@@ -0,0 +1,26 @@
+#ifndef __X86_PAGE_SHIFT_H__
+#define __X86_PAGE_SHIFT_H__
+
+#define L1_PAGETABLE_SHIFT      12
+#define L2_PAGETABLE_SHIFT      21
+#define L3_PAGETABLE_SHIFT      30
+#define L4_PAGETABLE_SHIFT      39
+#define PAGE_SHIFT              L1_PAGETABLE_SHIFT
+#define SUPERPAGE_SHIFT         L2_PAGETABLE_SHIFT
+#define ROOT_PAGETABLE_SHIFT    L4_PAGETABLE_SHIFT
+
+#define PAGETABLE_ORDER         9
+#define L1_PAGETABLE_ENTRIES    (1 << PAGETABLE_ORDER)
+#define L2_PAGETABLE_ENTRIES    (1 << PAGETABLE_ORDER)
+#define L3_PAGETABLE_ENTRIES    (1 << PAGETABLE_ORDER)
+#define L4_PAGETABLE_ENTRIES    (1 << PAGETABLE_ORDER)
+#define ROOT_PAGETABLE_ENTRIES  L4_PAGETABLE_ENTRIES
+
+#define SUPERPAGE_ORDER         PAGETABLE_ORDER
+#define SUPERPAGE_PAGES         (1 << SUPERPAGE_ORDER)
+
+/* These are architectural limits. */
+#define PADDR_BITS              52
+#define VADDR_BITS              48
+
+#endif /* __X86_PAGE_SHIFT_H__ */
--- a/xen/include/asm-x86/uaccess.h
+++ b/xen/include/asm-x86/uaccess.h
@@ -6,7 +6,6 @@
  #include <xen/errno.h>
  #include <xen/prefetch.h>
  #include <asm/asm_defns.h>
-#include <asm/page.h>

#include <asm/x86_64/uaccess.h>--- a/xen/include/asm-x86/x86_64/page.h

+++ b/xen/include/asm-x86/x86_64/page.h
@@ -2,31 +2,8 @@
  #ifndef __X86_64_PAGE_H__
  #define __X86_64_PAGE_H__

-#define L1_PAGETABLE_SHIFT 12

-#define L2_PAGETABLE_SHIFT      21
-#define L3_PAGETABLE_SHIFT      30
-#define L4_PAGETABLE_SHIFT      39
-#define PAGE_SHIFT              L1_PAGETABLE_SHIFT
-#define SUPERPAGE_SHIFT         L2_PAGETABLE_SHIFT
-#define ROOT_PAGETABLE_SHIFT    L4_PAGETABLE_SHIFT
-
-#define PAGETABLE_ORDER         9
-#define L1_PAGETABLE_ENTRIES    (1<<PAGETABLE_ORDER)
-#define L2_PAGETABLE_ENTRIES    (1<<PAGETABLE_ORDER)
-#define L3_PAGETABLE_ENTRIES    (1<<PAGETABLE_ORDER)
-#define L4_PAGETABLE_ENTRIES    (1<<PAGETABLE_ORDER)
-#define ROOT_PAGETABLE_ENTRIES  L4_PAGETABLE_ENTRIES
-#define SUPERPAGE_ORDER         PAGETABLE_ORDER
-#define SUPERPAGE_PAGES         (1<<SUPERPAGE_ORDER)
-
  #define __XEN_VIRT_START        XEN_VIRT_START

-/* These are architectural limits. Current CPUs support only 40-bit phys. */

-#define PADDR_BITS              52
-#define VADDR_BITS              48
-#define PADDR_MASK              ((_AC(1,UL) << PADDR_BITS) - 1)
-#define VADDR_MASK              ((_AC(1,UL) << VADDR_BITS) - 1)
-
  #define VADDR_TOP_BIT           (1UL << (VADDR_BITS - 1))
  #define CANONICAL_MASK          (~0UL & ~VADDR_MASK)

--- a/xen/include/xen/gdbstub.h

+++ b/xen/include/xen/gdbstub.h
@@ -20,8 +20,8 @@
  #ifndef __XEN_GDBSTUB_H__
  #define __XEN_GDBSTUB_H__

+#include <xen/page-size.h>

  #include <asm/atomic.h>
-#include <asm/page.h>

#ifdef CONFIG_CRASH_DEBUG--- a/xen/include/xen/grant_table.h

+++ b/xen/include/xen/grant_table.h
@@ -26,7 +26,6 @@
  #include <xen/mm.h>
  #include <xen/rwlock.h>
  #include <public/grant_table.h>
-#include <asm/page.h>
  #include <asm/grant_table.h>

#ifdef CONFIG_GRANT_TABLE

--- /dev/null
+++ b/xen/include/xen/page-size.h
@@ -0,0 +1,18 @@
+#ifndef __XEN_PAGE_SIZE_H__
+#define __XEN_PAGE_SIZE_H__
+
+#include <xen/const.h>
+#include <asm/page-bits.h>
+
+/*
+ * It is important that the masks are signed quantities. This ensures that
+ * the compiler sign-extends a 32-bit mask to 64 bits if that is required.
+ */
+#define PAGE_SIZE           (_AC(1,L) << PAGE_SHIFT)
+#define PAGE_MASK           (~(PAGE_SIZE-1))
+#define PAGE_OFFSET(ptr)   ((unsigned long)(ptr) & ~PAGE_MASK)
+
+#define PADDR_MASK          ((_AC(1,ULL) << PADDR_BITS) - 1)
+#define VADDR_MASK          (~_AC(0,UL) >> (BITS_PER_LONG - VADDR_BITS))
+
+#endif /* __XEN_PAGE_SIZE__ */
--- a/xen/include/xen/pfn.h
+++ b/xen/include/xen/pfn.h
@@ -1,7 +1,7 @@
  #ifndef __XEN_PFN_H__
  #define __XEN_PFN_H__

-#include <asm/page.h>

+#include <xen/page-size.h>

#define PFN_DOWN(x) ((x) >> PAGE_SHIFT)

  #define PFN_UP(x)     (((x) + PAGE_SIZE-1) >> PAGE_SHIFT)
--- a/xen/include/xen/vmap.h
+++ b/xen/include/xen/vmap.h
@@ -2,7 +2,7 @@
  #define __XEN_VMAP_H__

#include <xen/mm.h>

-#include <asm/page.h>
+#include <xen/page-size.h>

enum vmap_region {

      VMAP_DEFAULT,


--
Julien Grall

References:
- [PATCH v2 0/2] a tiny bit of header disentangling
  - From: Jan Beulich
- [PATCH v2 1/2] include: don't use asm/page.h from common headers
  - From: Jan Beulich

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