linux_dsm_epyc7002/arch/s390/include/asm/pgalloc.h
Michael Holzheu 11a247e376 s390: Remove VLAIS in ptff() and clear_table()
The ptff() and clear_table() functions use the gcc extension "variable
length arrays in structures" (VLAIS) to define in the inline assembler
constraints the area of the clobbered memory. This extension will most
likely never be supported by LLVM/Clang.

Since currently BPF programs are compiled with LLVM, this leads to the
following compile errors:

 $ cd samples/bpf
 $ make

 In file included from /root/linux-master/samples/bpf/tracex1_kern.c:8:
 In file included from ./include/linux/netdevice.h:44:
 ...
 In file included from ./arch/s390/include/asm/mmu_context.h:10:
  ./arch/s390/include/asm/pgalloc.h:30:24: error: fields must have a
  constant size: 'variable length array in structure' extension will never
  be supported
         typedef struct { char _[n]; } addrtype;

 In file included from /root/linux-master/samples/bpf/tracex1_kern.c:7:
 In file included from ./include/linux/skbuff.h:18:
 ...
 In file included from ./include/linux/jiffies.h:8:
 In file included from ./include/linux/timex.h:65:
  ./arch/s390/include/asm/timex.h:105:24: error: fields must have a
  constant size: 'variable length array in structure' extension will never
  be supported
        typedef struct { char _[len]; } addrtype;

To fix this do the following:

 - Convert ptff() into a macro that then uses a fixed size array
   when expanded.
 - Convert the clear_table() function and use an inline assembly
   with fixed size array in a loop.
   The runtime performance of the new version is even better than
   the old version (tested with EC12/z13 and gcc 4.8.5/6.2.1 with
   "-march=z196 -O2").

Reported-by: Zvonko Kosic <zvonko.kosic@de.ibm.com>
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2016-12-07 07:22:30 +01:00

145 lines
3.8 KiB
C

/*
* S390 version
* Copyright IBM Corp. 1999, 2000
* Author(s): Hartmut Penner (hp@de.ibm.com)
* Martin Schwidefsky (schwidefsky@de.ibm.com)
*
* Derived from "include/asm-i386/pgalloc.h"
* Copyright (C) 1994 Linus Torvalds
*/
#ifndef _S390_PGALLOC_H
#define _S390_PGALLOC_H
#include <linux/threads.h>
#include <linux/gfp.h>
#include <linux/mm.h>
unsigned long *crst_table_alloc(struct mm_struct *);
void crst_table_free(struct mm_struct *, unsigned long *);
unsigned long *page_table_alloc(struct mm_struct *);
struct page *page_table_alloc_pgste(struct mm_struct *mm);
void page_table_free(struct mm_struct *, unsigned long *);
void page_table_free_rcu(struct mmu_gather *, unsigned long *, unsigned long);
void page_table_free_pgste(struct page *page);
extern int page_table_allocate_pgste;
static inline void clear_table(unsigned long *s, unsigned long val, size_t n)
{
struct addrtype { char _[256]; };
int i;
for (i = 0; i < n; i += 256) {
*s = val;
asm volatile(
"mvc 8(248,%[s]),0(%[s])\n"
: "+m" (*(struct addrtype *) s)
: [s] "a" (s));
s += 256 / sizeof(long);
}
}
static inline void crst_table_init(unsigned long *crst, unsigned long entry)
{
clear_table(crst, entry, sizeof(unsigned long)*2048);
}
static inline unsigned long pgd_entry_type(struct mm_struct *mm)
{
if (mm->context.asce_limit <= (1UL << 31))
return _SEGMENT_ENTRY_EMPTY;
if (mm->context.asce_limit <= (1UL << 42))
return _REGION3_ENTRY_EMPTY;
return _REGION2_ENTRY_EMPTY;
}
int crst_table_upgrade(struct mm_struct *);
void crst_table_downgrade(struct mm_struct *);
static inline pud_t *pud_alloc_one(struct mm_struct *mm, unsigned long address)
{
unsigned long *table = crst_table_alloc(mm);
if (table)
crst_table_init(table, _REGION3_ENTRY_EMPTY);
return (pud_t *) table;
}
#define pud_free(mm, pud) crst_table_free(mm, (unsigned long *) pud)
static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long vmaddr)
{
unsigned long *table = crst_table_alloc(mm);
if (!table)
return NULL;
crst_table_init(table, _SEGMENT_ENTRY_EMPTY);
if (!pgtable_pmd_page_ctor(virt_to_page(table))) {
crst_table_free(mm, table);
return NULL;
}
return (pmd_t *) table;
}
static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd)
{
pgtable_pmd_page_dtor(virt_to_page(pmd));
crst_table_free(mm, (unsigned long *) pmd);
}
static inline void pgd_populate(struct mm_struct *mm, pgd_t *pgd, pud_t *pud)
{
pgd_val(*pgd) = _REGION2_ENTRY | __pa(pud);
}
static inline void pud_populate(struct mm_struct *mm, pud_t *pud, pmd_t *pmd)
{
pud_val(*pud) = _REGION3_ENTRY | __pa(pmd);
}
static inline pgd_t *pgd_alloc(struct mm_struct *mm)
{
unsigned long *table = crst_table_alloc(mm);
if (!table)
return NULL;
if (mm->context.asce_limit == (1UL << 31)) {
/* Forking a compat process with 2 page table levels */
if (!pgtable_pmd_page_ctor(virt_to_page(table))) {
crst_table_free(mm, table);
return NULL;
}
}
return (pgd_t *) table;
}
static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
{
if (mm->context.asce_limit == (1UL << 31))
pgtable_pmd_page_dtor(virt_to_page(pgd));
crst_table_free(mm, (unsigned long *) pgd);
}
static inline void pmd_populate(struct mm_struct *mm,
pmd_t *pmd, pgtable_t pte)
{
pmd_val(*pmd) = _SEGMENT_ENTRY + __pa(pte);
}
#define pmd_populate_kernel(mm, pmd, pte) pmd_populate(mm, pmd, pte)
#define pmd_pgtable(pmd) \
(pgtable_t)(pmd_val(pmd) & -sizeof(pte_t)*PTRS_PER_PTE)
/*
* page table entry allocation/free routines.
*/
#define pte_alloc_one_kernel(mm, vmaddr) ((pte_t *) page_table_alloc(mm))
#define pte_alloc_one(mm, vmaddr) ((pte_t *) page_table_alloc(mm))
#define pte_free_kernel(mm, pte) page_table_free(mm, (unsigned long *) pte)
#define pte_free(mm, pte) page_table_free(mm, (unsigned long *) pte)
extern void rcu_table_freelist_finish(void);
#endif /* _S390_PGALLOC_H */