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mm: Define VM_DROPPABLE for powerpc/32

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Commit 9651fcedf7 ("mm: add MAP_DROPPABLE for designating always
lazily freeable mappings") only adds VM_DROPPABLE for 64 bits
architectures.

In order to also use the getrandom vDSO implementation on powerpc/32,
use VM_ARCH_1 for VM_DROPPABLE on powerpc/32. This is possible because
VM_ARCH_1 is used for VM_SAO on powerpc and VM_SAO is only for
powerpc/64. It is used in combination with PROT_SAO in some parts of
code that are restricted to CONFIG_PPC64 through #ifdefs, it is
therefore possible to define VM_SAO for CONFIG_PPC64 only.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
This commit is contained in:
Christophe Leroy 2024-09-02 21:17:18 +02:00 committed by Jason A. Donenfeld
parent c73049389e
commit d175ee98fe
3 changed files with 8 additions and 4 deletions
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4
fs/proc/task_mmu.c
View file

@ -987,8 +987,10 @@ static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma)
#ifdef CONFIG_X86_USER_SHADOW_STACK
[ilog2(VM_SHADOW_STACK)] = "ss",
#endif
#ifdef CONFIG_64BIT
#if defined(CONFIG_64BIT) || defined(CONFIG_PPC32)
[ilog2(VM_DROPPABLE)] = "dp",
#endif
#ifdef CONFIG_64BIT
[ilog2(VM_SEALED)] = "sl",
#endif
};

4
include/linux/mm.h
View file

@ -359,7 +359,7 @@ extern unsigned int kobjsize(const void *objp);
#if defined(CONFIG_X86)
# define VM_PAT VM_ARCH_1 /* PAT reserves whole VMA at once (x86) */
#elif defined(CONFIG_PPC)
#elif defined(CONFIG_PPC64)
# define VM_SAO VM_ARCH_1 /* Strong Access Ordering (powerpc) */
#elif defined(CONFIG_PARISC)
# define VM_GROWSUP VM_ARCH_1
@ -409,6 +409,8 @@ extern unsigned int kobjsize(const void *objp);
#ifdef CONFIG_64BIT
#define VM_DROPPABLE_BIT 40
#define VM_DROPPABLE BIT(VM_DROPPABLE_BIT)
#elif defined(CONFIG_PPC32)
#define VM_DROPPABLE VM_ARCH_1
#else
#define VM_DROPPABLE VM_NONE
#endif

4
include/trace/events/mmflags.h
View file

@ -143,7 +143,7 @@ IF_HAVE_PG_ARCH_X(arch_3)
#if defined(CONFIG_X86)
#define __VM_ARCH_SPECIFIC_1 {VM_PAT, "pat" }
#elif defined(CONFIG_PPC)
#elif defined(CONFIG_PPC64)
#define __VM_ARCH_SPECIFIC_1 {VM_SAO, "sao" }
#elif defined(CONFIG_PARISC)
#define __VM_ARCH_SPECIFIC_1 {VM_GROWSUP, "growsup" }
@ -165,7 +165,7 @@ IF_HAVE_PG_ARCH_X(arch_3)
# define IF_HAVE_UFFD_MINOR(flag, name)
#endif
#ifdef CONFIG_64BIT
#if defined(CONFIG_64BIT) || defined(CONFIG_PPC32)
# define IF_HAVE_VM_DROPPABLE(flag, name) {flag, name},
#else
# define IF_HAVE_VM_DROPPABLE(flag, name)