* [PATCH v2 0/5] Implement huge VMAP and VMALLOC on powerpc 8xx
From: Christophe Leroy @ 2021-05-12 5:00 UTC (permalink / raw)
To: Andrew Morton, Nicholas Piggin, Mike Kravetz, Mike Rapoport
Cc: linux-arch, linux-kernel, linux-mm, sparclinux, linuxppc-dev,
linux-arm-kernel
This series implements huge VMAP and VMALLOC on powerpc 8xx.
Powerpc 8xx has 4 page sizes:
- 4k
- 16k
- 512k
- 8M
At the time being, vmalloc and vmap only support huge pages which are
leaf at PMD level.
Here the PMD level is 4M, it doesn't correspond to any supported
page size.
For now, implement use of 16k and 512k pages which is done
at PTE level.
Support of 8M pages will be implemented later, it requires use of
hugepd tables.
To allow this, the architecture provides two functions:
- arch_vmap_pte_range_map_size() which tells vmap_pte_range() what
page size to use. A stub returning PAGE_SIZE is provided when the
architecture doesn't provide this function.
- arch_vmap_pte_supported_shift() which tells __vmalloc_node_range()
what page shift to use for a given area size. A stub returning
PAGE_SHIFT is provided when the architecture doesn't provide this
function.
The main change in v2 compared to the RFC is that powerpc 8xx
specificities are not plugged anymore directly inside vmalloc code.
Christophe Leroy (5):
mm/hugetlb: Change parameters of arch_make_huge_pte()
mm/pgtable: Add stubs for {pmd/pub}_{set/clear}_huge
mm/vmalloc: Enable mapping of huge pages at pte level in vmap
mm/vmalloc: Enable mapping of huge pages at pte level in vmalloc
powerpc/8xx: Add support for huge pages on VMAP and VMALLOC
arch/arm64/include/asm/hugetlb.h | 3 +-
arch/arm64/mm/hugetlbpage.c | 5 +--
arch/powerpc/Kconfig | 2 +-
.../include/asm/nohash/32/hugetlb-8xx.h | 5 +--
arch/powerpc/include/asm/nohash/32/mmu-8xx.h | 43 +++++++++++++++++++
arch/sparc/include/asm/pgtable_64.h | 3 +-
arch/sparc/mm/hugetlbpage.c | 6 +--
include/linux/hugetlb.h | 4 +-
include/linux/pgtable.h | 26 ++++++++++-
include/linux/vmalloc.h | 15 +++++++
mm/hugetlb.c | 6 ++-
mm/migrate.c | 4 +-
mm/vmalloc.c | 34 +++++++++++----
13 files changed, 126 insertions(+), 30 deletions(-)
--
2.25.0
^ permalink raw reply
* [PATCH v2 1/5] mm/hugetlb: Change parameters of arch_make_huge_pte()
From: Christophe Leroy @ 2021-05-12 5:00 UTC (permalink / raw)
To: Andrew Morton, Nicholas Piggin, Mike Kravetz, Mike Rapoport
Cc: linux-arch, linux-kernel, linux-mm, sparclinux, linuxppc-dev,
linux-arm-kernel
In-Reply-To: <cover.1620795204.git.christophe.leroy@csgroup.eu>
At the time being, arch_make_huge_pte() has the following prototype:
pte_t arch_make_huge_pte(pte_t entry, struct vm_area_struct *vma,
struct page *page, int writable);
vma is used to get the pages shift or size.
vma is also used on Sparc to get vm_flags.
page is not used.
writable is not used.
In order to use this function without a vma, replace vma by shift
and flags. Also remove the used parameters.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Acked-by: Mike Kravetz <mike.kravetz@oracle.com>
---
arch/arm64/include/asm/hugetlb.h | 3 +--
arch/arm64/mm/hugetlbpage.c | 5 ++---
arch/powerpc/include/asm/nohash/32/hugetlb-8xx.h | 5 ++---
arch/sparc/include/asm/pgtable_64.h | 3 +--
arch/sparc/mm/hugetlbpage.c | 6 ++----
include/linux/hugetlb.h | 4 ++--
mm/hugetlb.c | 6 ++++--
mm/migrate.c | 4 +++-
8 files changed, 17 insertions(+), 19 deletions(-)
diff --git a/arch/arm64/include/asm/hugetlb.h b/arch/arm64/include/asm/hugetlb.h
index 5abf91e3494c..1242f71937f8 100644
--- a/arch/arm64/include/asm/hugetlb.h
+++ b/arch/arm64/include/asm/hugetlb.h
@@ -23,8 +23,7 @@ static inline void arch_clear_hugepage_flags(struct page *page)
}
#define arch_clear_hugepage_flags arch_clear_hugepage_flags
-extern pte_t arch_make_huge_pte(pte_t entry, struct vm_area_struct *vma,
- struct page *page, int writable);
+pte_t arch_make_huge_pte(pte_t entry, unsigned int shift, vm_flags_t flags);
#define arch_make_huge_pte arch_make_huge_pte
#define __HAVE_ARCH_HUGE_SET_HUGE_PTE_AT
extern void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
index 58987a98e179..23505fc35324 100644
--- a/arch/arm64/mm/hugetlbpage.c
+++ b/arch/arm64/mm/hugetlbpage.c
@@ -339,10 +339,9 @@ pte_t *huge_pte_offset(struct mm_struct *mm,
return NULL;
}
-pte_t arch_make_huge_pte(pte_t entry, struct vm_area_struct *vma,
- struct page *page, int writable)
+pte_t arch_make_huge_pte(pte_t entry, unsigned int shift, vm_flags_t flags)
{
- size_t pagesize = huge_page_size(hstate_vma(vma));
+ size_t pagesize = 1UL << shift;
if (pagesize == CONT_PTE_SIZE) {
entry = pte_mkcont(entry);
diff --git a/arch/powerpc/include/asm/nohash/32/hugetlb-8xx.h b/arch/powerpc/include/asm/nohash/32/hugetlb-8xx.h
index 39be9aea86db..64b6c608eca4 100644
--- a/arch/powerpc/include/asm/nohash/32/hugetlb-8xx.h
+++ b/arch/powerpc/include/asm/nohash/32/hugetlb-8xx.h
@@ -66,10 +66,9 @@ static inline void huge_ptep_set_wrprotect(struct mm_struct *mm,
}
#ifdef CONFIG_PPC_4K_PAGES
-static inline pte_t arch_make_huge_pte(pte_t entry, struct vm_area_struct *vma,
- struct page *page, int writable)
+static inline pte_t arch_make_huge_pte(pte_t entry, unsigned int shift, vm_flags_t flags)
{
- size_t size = huge_page_size(hstate_vma(vma));
+ size_t size = 1UL << shift;
if (size == SZ_16K)
return __pte(pte_val(entry) & ~_PAGE_HUGE);
diff --git a/arch/sparc/include/asm/pgtable_64.h b/arch/sparc/include/asm/pgtable_64.h
index 550d3904de65..2cd80a0a9795 100644
--- a/arch/sparc/include/asm/pgtable_64.h
+++ b/arch/sparc/include/asm/pgtable_64.h
@@ -377,8 +377,7 @@ static inline pgprot_t pgprot_noncached(pgprot_t prot)
#define pgprot_noncached pgprot_noncached
#if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
-extern pte_t arch_make_huge_pte(pte_t entry, struct vm_area_struct *vma,
- struct page *page, int writable);
+pte_t arch_make_huge_pte(pte_t entry, unsigned int shift, vm_flags_t flags);
#define arch_make_huge_pte arch_make_huge_pte
static inline unsigned long __pte_default_huge_mask(void)
{
diff --git a/arch/sparc/mm/hugetlbpage.c b/arch/sparc/mm/hugetlbpage.c
index 04d8790f6c32..0f49fada2093 100644
--- a/arch/sparc/mm/hugetlbpage.c
+++ b/arch/sparc/mm/hugetlbpage.c
@@ -177,10 +177,8 @@ static pte_t hugepage_shift_to_tte(pte_t entry, unsigned int shift)
return sun4u_hugepage_shift_to_tte(entry, shift);
}
-pte_t arch_make_huge_pte(pte_t entry, struct vm_area_struct *vma,
- struct page *page, int writeable)
+pte_t arch_make_huge_pte(pte_t entry, unsigned int shift, vm_flags_t flags)
{
- unsigned int shift = huge_page_shift(hstate_vma(vma));
pte_t pte;
pte = hugepage_shift_to_tte(entry, shift);
@@ -188,7 +186,7 @@ pte_t arch_make_huge_pte(pte_t entry, struct vm_area_struct *vma,
#ifdef CONFIG_SPARC64
/* If this vma has ADI enabled on it, turn on TTE.mcd
*/
- if (vma->vm_flags & VM_SPARC_ADI)
+ if (flags & VM_SPARC_ADI)
return pte_mkmcd(pte);
else
return pte_mknotmcd(pte);
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index b92f25ccef58..24f47981c166 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -710,8 +710,8 @@ static inline void arch_clear_hugepage_flags(struct page *page) { }
#endif
#ifndef arch_make_huge_pte
-static inline pte_t arch_make_huge_pte(pte_t entry, struct vm_area_struct *vma,
- struct page *page, int writable)
+static inline pte_t arch_make_huge_pte(pte_t entry, unsigned int shift,
+ vm_flags_t flags)
{
return entry;
}
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 3db405dea3dc..396285b16dd8 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -3856,6 +3856,7 @@ static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
int writable)
{
pte_t entry;
+ unsigned int shift = huge_page_shift(hstate_vma(vma));
if (writable) {
entry = huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page,
@@ -3866,7 +3867,7 @@ static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
}
entry = pte_mkyoung(entry);
entry = pte_mkhuge(entry);
- entry = arch_make_huge_pte(entry, vma, page, writable);
+ entry = arch_make_huge_pte(entry, shift, vma->vm_flags);
return entry;
}
@@ -5250,10 +5251,11 @@ unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
}
if (!huge_pte_none(pte)) {
pte_t old_pte;
+ unsigned int shift = huge_page_shift(hstate_vma(vma));
old_pte = huge_ptep_modify_prot_start(vma, address, ptep);
pte = pte_mkhuge(huge_pte_modify(old_pte, newprot));
- pte = arch_make_huge_pte(pte, vma, NULL, 0);
+ pte = arch_make_huge_pte(pte, shift, vma->vm_flags);
huge_ptep_modify_prot_commit(vma, address, ptep, old_pte, pte);
pages++;
}
diff --git a/mm/migrate.c b/mm/migrate.c
index b234c3f3acb7..49ee64cd2ff3 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -226,8 +226,10 @@ static bool remove_migration_pte(struct page *page, struct vm_area_struct *vma,
#ifdef CONFIG_HUGETLB_PAGE
if (PageHuge(new)) {
+ unsigned int shift = huge_page_shift(hstate_vma(vma));
+
pte = pte_mkhuge(pte);
- pte = arch_make_huge_pte(pte, vma, new, 0);
+ pte = arch_make_huge_pte(pte, shift, vma->vm_flags);
set_huge_pte_at(vma->vm_mm, pvmw.address, pvmw.pte, pte);
if (PageAnon(new))
hugepage_add_anon_rmap(new, vma, pvmw.address);
--
2.25.0
^ permalink raw reply related
* [PATCH v2 2/5] mm/pgtable: Add stubs for {pmd/pub}_{set/clear}_huge
From: Christophe Leroy @ 2021-05-12 5:00 UTC (permalink / raw)
To: Andrew Morton, Nicholas Piggin, Mike Kravetz, Mike Rapoport
Cc: linux-arch, linux-kernel, linux-mm, sparclinux, linuxppc-dev,
linux-arm-kernel
In-Reply-To: <cover.1620795204.git.christophe.leroy@csgroup.eu>
For architectures with no PMD and/or no PUD, add stubs
similar to what we have for architectures without P4D.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
include/linux/pgtable.h | 26 +++++++++++++++++++++++++-
1 file changed, 25 insertions(+), 1 deletion(-)
diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index 46b13780c2c8..d41474a2d255 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -1371,10 +1371,34 @@ static inline int p4d_clear_huge(p4d_t *p4d)
}
#endif /* !__PAGETABLE_P4D_FOLDED */
+#ifndef __PAGETABLE_PUD_FOLDED
int pud_set_huge(pud_t *pud, phys_addr_t addr, pgprot_t prot);
-int pmd_set_huge(pmd_t *pmd, phys_addr_t addr, pgprot_t prot);
int pud_clear_huge(pud_t *pud);
+#else
+static inline int pud_set_huge(pud_t *pud, phys_addr_t addr, pgprot_t prot)
+{
+ return 0;
+}
+static inline int pud_clear_huge(pud_t *pud)
+{
+ return 0;
+}
+#endif /* !__PAGETABLE_PUD_FOLDED */
+
+#ifndef __PAGETABLE_PMD_FOLDED
+int pmd_set_huge(pmd_t *pmd, phys_addr_t addr, pgprot_t prot);
int pmd_clear_huge(pmd_t *pmd);
+#else
+static inline int pmd_set_huge(pmd_t *pmd, phys_addr_t addr, pgprot_t prot)
+{
+ return 0;
+}
+static inline int pmd_clear_huge(pmd_t *pmd)
+{
+ return 0;
+}
+#endif /* !__PAGETABLE_PMD_FOLDED */
+
int p4d_free_pud_page(p4d_t *p4d, unsigned long addr);
int pud_free_pmd_page(pud_t *pud, unsigned long addr);
int pmd_free_pte_page(pmd_t *pmd, unsigned long addr);
--
2.25.0
^ permalink raw reply related
* [PATCH v2 3/5] mm/vmalloc: Enable mapping of huge pages at pte level in vmap
From: Christophe Leroy @ 2021-05-12 5:01 UTC (permalink / raw)
To: Andrew Morton, Nicholas Piggin, Mike Kravetz, Mike Rapoport
Cc: linux-arch, linux-kernel, linux-mm, sparclinux, linuxppc-dev,
linux-arm-kernel
In-Reply-To: <cover.1620795204.git.christophe.leroy@csgroup.eu>
On some architectures like powerpc, there are huge pages that
are mapped at pte level.
Enable it in vmap.
For that, architectures can provide arch_vmap_pte_range_map_size()
that returns the size of pages to map at pte level.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
include/linux/vmalloc.h | 8 ++++++++
mm/vmalloc.c | 21 ++++++++++++++++++---
2 files changed, 26 insertions(+), 3 deletions(-)
diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
index 4d668abb6391..13c9b19ec923 100644
--- a/include/linux/vmalloc.h
+++ b/include/linux/vmalloc.h
@@ -104,6 +104,14 @@ static inline bool arch_vmap_pmd_supported(pgprot_t prot)
}
#endif
+#ifndef arch_vmap_pte_range_map_size
+static inline unsigned long arch_vmap_pte_range_map_size(unsigned long addr, unsigned long end,
+ u64 pfn, unsigned int max_page_shift)
+{
+ return PAGE_SIZE;
+}
+#endif
+
/*
* Highlevel APIs for driver use
*/
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index a13ac524f6ff..783d23b8c2f7 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -36,6 +36,7 @@
#include <linux/overflow.h>
#include <linux/pgtable.h>
#include <linux/uaccess.h>
+#include <linux/hugetlb.h>
#include <asm/tlbflush.h>
#include <asm/shmparam.h>
@@ -83,10 +84,11 @@ static void free_work(struct work_struct *w)
/*** Page table manipulation functions ***/
static int vmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
phys_addr_t phys_addr, pgprot_t prot,
- pgtbl_mod_mask *mask)
+ unsigned int max_page_shift, pgtbl_mod_mask *mask)
{
pte_t *pte;
u64 pfn;
+ unsigned long size = PAGE_SIZE;
pfn = phys_addr >> PAGE_SHIFT;
pte = pte_alloc_kernel_track(pmd, addr, mask);
@@ -94,9 +96,22 @@ static int vmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
return -ENOMEM;
do {
BUG_ON(!pte_none(*pte));
+
+#ifdef CONFIG_HUGETLB_PAGE
+ size = arch_vmap_pte_range_map_size(addr, end, pfn, max_page_shift);
+ if (size != PAGE_SIZE) {
+ pte_t entry = pfn_pte(pfn, prot);
+
+ entry = pte_mkhuge(entry);
+ entry = arch_make_huge_pte(entry, ilog2(size), 0);
+ set_huge_pte_at(&init_mm, addr, pte, entry);
+ pfn += PFN_DOWN(size);
+ continue;
+ }
+#endif
set_pte_at(&init_mm, addr, pte, pfn_pte(pfn, prot));
pfn++;
- } while (pte++, addr += PAGE_SIZE, addr != end);
+ } while (pte += PFN_DOWN(size), addr += size, addr != end);
*mask |= PGTBL_PTE_MODIFIED;
return 0;
}
@@ -145,7 +160,7 @@ static int vmap_pmd_range(pud_t *pud, unsigned long addr, unsigned long end,
continue;
}
- if (vmap_pte_range(pmd, addr, next, phys_addr, prot, mask))
+ if (vmap_pte_range(pmd, addr, next, phys_addr, prot, max_page_shift, mask))
return -ENOMEM;
} while (pmd++, phys_addr += (next - addr), addr = next, addr != end);
return 0;
--
2.25.0
^ permalink raw reply related
* [PATCH v2 4/5] mm/vmalloc: Enable mapping of huge pages at pte level in vmalloc
From: Christophe Leroy @ 2021-05-12 5:01 UTC (permalink / raw)
To: Andrew Morton, Nicholas Piggin, Mike Kravetz, Mike Rapoport
Cc: linux-arch, linux-kernel, linux-mm, sparclinux, linuxppc-dev,
linux-arm-kernel
In-Reply-To: <cover.1620795204.git.christophe.leroy@csgroup.eu>
On some architectures like powerpc, there are huge pages that
are mapped at pte level.
Enable it in vmalloc.
For that, architectures can provide arch_vmap_pte_supported_shift()
that returns the shift for pages to map at pte level.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
include/linux/vmalloc.h | 7 +++++++
mm/vmalloc.c | 13 +++++++------
2 files changed, 14 insertions(+), 6 deletions(-)
diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
index 13c9b19ec923..bf0a1b7a824e 100644
--- a/include/linux/vmalloc.h
+++ b/include/linux/vmalloc.h
@@ -112,6 +112,13 @@ static inline unsigned long arch_vmap_pte_range_map_size(unsigned long addr, uns
}
#endif
+#ifndef arch_vmap_pte_supported_shift
+static inline int arch_vmap_pte_supported_shift(unsigned long size)
+{
+ return PAGE_SHIFT;
+}
+#endif
+
/*
* Highlevel APIs for driver use
*/
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 783d23b8c2f7..3de5291c20cd 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -2895,8 +2895,7 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align,
return NULL;
}
- if (vmap_allow_huge && !(vm_flags & VM_NO_HUGE_VMAP) &&
- arch_vmap_pmd_supported(prot)) {
+ if (vmap_allow_huge && !(vm_flags & VM_NO_HUGE_VMAP)) {
unsigned long size_per_node;
/*
@@ -2909,11 +2908,13 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align,
size_per_node = size;
if (node == NUMA_NO_NODE)
size_per_node /= num_online_nodes();
- if (size_per_node >= PMD_SIZE) {
+ if (arch_vmap_pmd_supported(prot) && size_per_node >= PMD_SIZE)
shift = PMD_SHIFT;
- align = max(real_align, 1UL << shift);
- size = ALIGN(real_size, 1UL << shift);
- }
+ else
+ shift = arch_vmap_pte_supported_shift(size_per_node);
+
+ align = max(real_align, 1UL << shift);
+ size = ALIGN(real_size, 1UL << shift);
}
again:
--
2.25.0
^ permalink raw reply related
* [PATCH v2 5/5] powerpc/8xx: Add support for huge pages on VMAP and VMALLOC
From: Christophe Leroy @ 2021-05-12 5:01 UTC (permalink / raw)
To: Andrew Morton, Nicholas Piggin, Mike Kravetz, Mike Rapoport
Cc: linux-arch, linux-kernel, linux-mm, sparclinux, linuxppc-dev,
linux-arm-kernel
In-Reply-To: <cover.1620795204.git.christophe.leroy@csgroup.eu>
powerpc 8xx has 4 page sizes:
- 4k
- 16k
- 512k
- 8M
At the time being, vmalloc and vmap only support huge pages which are
leaf at PMD level.
Here the PMD level is 4M, it doesn't correspond to any supported
page size.
For now, implement use of 16k and 512k pages which is done
at PTE level.
Support of 8M pages will be implemented later, it requires vmalloc to
support hugepd tables.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
arch/powerpc/Kconfig | 2 +-
arch/powerpc/include/asm/nohash/32/mmu-8xx.h | 43 ++++++++++++++++++++
2 files changed, 44 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 088dd2afcfe4..ce3f59531b51 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -187,7 +187,7 @@ config PPC
select GENERIC_VDSO_TIME_NS
select HAVE_ARCH_AUDITSYSCALL
select HAVE_ARCH_HUGE_VMALLOC if HAVE_ARCH_HUGE_VMAP
- select HAVE_ARCH_HUGE_VMAP if PPC_BOOK3S_64 && PPC_RADIX_MMU
+ select HAVE_ARCH_HUGE_VMAP if PPC_RADIX_MMU || PPC_8xx
select HAVE_ARCH_JUMP_LABEL
select HAVE_ARCH_JUMP_LABEL_RELATIVE
select HAVE_ARCH_KASAN if PPC32 && PPC_PAGE_SHIFT <= 14
diff --git a/arch/powerpc/include/asm/nohash/32/mmu-8xx.h b/arch/powerpc/include/asm/nohash/32/mmu-8xx.h
index 6e4faa0a9b35..997cec973406 100644
--- a/arch/powerpc/include/asm/nohash/32/mmu-8xx.h
+++ b/arch/powerpc/include/asm/nohash/32/mmu-8xx.h
@@ -178,6 +178,7 @@
#ifndef __ASSEMBLY__
#include <linux/mmdebug.h>
+#include <linux/sizes.h>
void mmu_pin_tlb(unsigned long top, bool readonly);
@@ -225,6 +226,48 @@ static inline unsigned int mmu_psize_to_shift(unsigned int mmu_psize)
BUG();
}
+static inline bool arch_vmap_try_size(unsigned long addr, unsigned long end, u64 pfn,
+ unsigned int max_page_shift, unsigned long size)
+{
+ if (end - addr < size)
+ return false;
+
+ if ((1UL << max_page_shift) < size)
+ return false;
+
+ if (!IS_ALIGNED(addr, size))
+ return false;
+
+ if (!IS_ALIGNED(PFN_PHYS(pfn), size))
+ return false;
+
+ return true;
+}
+
+static inline unsigned long arch_vmap_pte_range_map_size(unsigned long addr, unsigned long end,
+ u64 pfn, unsigned int max_page_shift)
+{
+ if (arch_vmap_try_size(addr, end, pfn, max_page_shift, SZ_512K))
+ return SZ_512K;
+ if (PAGE_SIZE == SZ_16K)
+ return SZ_16K;
+ if (arch_vmap_try_size(addr, end, pfn, max_page_shift, SZ_16K))
+ return SZ_16K;
+ return PAGE_SIZE;
+}
+#define arch_vmap_pte_range_map_size arch_vmap_pte_range_map_size
+
+static inline int arch_vmap_pte_supported_shift(unsigned long size)
+{
+ if (size >= SZ_512K)
+ return 19;
+ else if (size >= SZ_16K)
+ return 14;
+ else
+ return PAGE_SHIFT;
+}
+#define arch_vmap_pte_supported_shift arch_vmap_pte_supported_shift
+
/* patch sites */
extern s32 patch__itlbmiss_exit_1, patch__dtlbmiss_exit_1;
extern s32 patch__itlbmiss_perf, patch__dtlbmiss_perf;
--
2.25.0
^ permalink raw reply related
* Re: [PATCH kernel v2] powerpc/makefile: Do not redefine $(CPP) for preprocessor
From: Alexey Kardashevskiy @ 2021-05-11 13:30 UTC (permalink / raw)
To: Segher Boessenkool
Cc: Michal Marek, linux-kbuild, Masahiro Yamada, Nick Desaulniers,
linux-kernel, Nicholas Piggin, Nathan Chancellor,
clang-built-linux, linuxppc-dev
In-Reply-To: <20210511112019.GK10366@gate.crashing.org>
[-- Attachment #1: Type: text/plain, Size: 2116 bytes --]
On 11 May 2021 21:24:55 Segher Boessenkool <segher@kernel.crashing.org> wrote:
> Hi!
>
> On Tue, May 11, 2021 at 02:48:12PM +1000, Alexey Kardashevskiy wrote:
>> --- a/arch/powerpc/kernel/vdso32/Makefile
>> +++ b/arch/powerpc/kernel/vdso32/Makefile
>> @@ -44,7 +44,7 @@ asflags-y := -D__VDSO32__ -s
>>
>> obj-y += vdso32_wrapper.o
>> targets += vdso32.lds
>> -CPPFLAGS_vdso32.lds += -P -C -Upowerpc
>> +CPPFLAGS_vdso32.lds += -C
>>
>> # link rule for the .so file, .lds has to be first
>> $(obj)/vdso32.so.dbg: $(src)/vdso32.lds $(obj-vdso32)
>> $(obj)/vgettimeofday.o FORCE
>
>> --- a/arch/powerpc/kernel/vdso64/Makefile
>> +++ b/arch/powerpc/kernel/vdso64/Makefile
>> @@ -30,7 +30,7 @@ ccflags-y := -shared -fno-common -fno-builtin -nostdlib \
>> asflags-y := -D__VDSO64__ -s
>>
>> targets += vdso64.lds
>> -CPPFLAGS_vdso64.lds += -P -C -U$(ARCH)
>> +CPPFLAGS_vdso64.lds += -C
>>
>> # link rule for the .so file, .lds has to be first
>> $(obj)/vdso64.so.dbg: $(src)/vdso64.lds $(obj-vdso64)
>> $(obj)/vgettimeofday.o FORCE
>
> Why are you removing -P and -Upowerpc here? "powerpc" is a predefined
> macro on powerpc-linux (no underscores or anything, just the bareword).
> This is historical, like "unix" and "linux". If you use the C
> preprocessor for things that are not C code (like the kernel does here)
> you need to undefine these macros, if anything in the files you run
> through the preprocessor contains those words, or funny / strange / bad
> things will happen. Presumably at some time in the past it did contain
> "powerpc" somewhere.
>
> -P is to inhibit line number output. Whatever consumes the
> preprocessor output will have to handle line directives if you remove
> this flag. Did you check if this will work for everything that uses
> $(CPP)?
i don't know about everything for sure but i checked few configs and in all
cases (except vdso) $CPP was receiving cflags.
>
> In any case, please mention the reasoning (and the fact that you are
> removing these flags!) in the commit message. Thanks!
but i did mention this, the last paragraph... they are duplicated.
>
>
> Segher
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^ permalink raw reply
* Re: [PATCH v3 1/1] kernel.h: Split out panic and oops helpers
From: Alex Elder @ 2021-05-11 14:35 UTC (permalink / raw)
To: Andy Shevchenko
Cc: linux-hyperv, linux-remoteproc, linux-fbdev, dri-devel,
linux-mips, sparclinux, linux-clk, linux-leds, linux-arch,
linux-s390, linux-staging, bcm-kernel-feedback-list, xen-devel,
linux-xtensa, linux-pm, coresight, linux-um, rcu,
openipmi-developer, linux-arm-kernel, linux-edac, linux-parisc,
netdev, kexec, linux-kernel, linux-alpha, linux-fsdevel,
linuxppc-dev
In-Reply-To: <20210511074137.33666-1-andriy.shevchenko@linux.intel.com>
On 5/11/21 2:41 AM, Andy Shevchenko wrote:
> kernel.h is being used as a dump for all kinds of stuff for a long time.
> Here is the attempt to start cleaning it up by splitting out panic and
> oops helpers.
>
> There are several purposes of doing this:
> - dropping dependency in bug.h
> - dropping a loop by moving out panic_notifier.h
> - unload kernel.h from something which has its own domain
>
> At the same time convert users tree-wide to use new headers, although
> for the time being include new header back to kernel.h to avoid twisted
> indirected includes for existing users.
>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> Acked-by: Mike Rapoport <rppt@linux.ibm.com>
> Acked-by: Corey Minyard <cminyard@mvista.com>
> Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
> Acked-by: Arnd Bergmann <arnd@arndb.de>
> Acked-by: Kees Cook <keescook@chromium.org>
> Acked-by: Wei Liu <wei.liu@kernel.org>
> Acked-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
> Co-developed-by: Andrew Morton <akpm@linux-foundation.org>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> Acked-by: Sebastian Reichel <sre@kernel.org>
> Acked-by: Luis Chamberlain <mcgrof@kernel.org>
> Acked-by: Stephen Boyd <sboyd@kernel.org>
> Acked-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
> Acked-by: Helge Deller <deller@gmx.de> # parisc
> ---
> v3: rebased on top of v5.13-rc1, collected a few more tags
>
> Note WRT Andrew's SoB tag above: I have added it since part of the cases
> I took from him. Andrew, feel free to amend or tell me how you want me
> to do.
>
Acked-by: Alex Elder <elder@kernel.org>
. . .
> diff --git a/drivers/net/ipa/ipa_smp2p.c b/drivers/net/ipa/ipa_smp2p.c
> index a5f7a79a1923..34b68dc43886 100644
> --- a/drivers/net/ipa/ipa_smp2p.c
> +++ b/drivers/net/ipa/ipa_smp2p.c
> @@ -8,6 +8,7 @@
> #include <linux/device.h>
> #include <linux/interrupt.h>
> #include <linux/notifier.h>
> +#include <linux/panic_notifier.h>
> #include <linux/soc/qcom/smem.h>
> #include <linux/soc/qcom/smem_state.h>
>
. . .
^ permalink raw reply
* [PATCH 1/5] powerpc/kuap: Force inlining of all first level KUAP helpers.
From: Christophe Leroy @ 2021-05-12 8:35 UTC (permalink / raw)
To: Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman
Cc: linuxppc-dev, linux-kernel
All KUAP helpers defined in asm/kup.h are single line functions
that should be inlined. But on book3s/32 build, we get many
instances of <prevent_write_to_user.constprop.0>.
Force inlining of those helpers.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
arch/powerpc/include/asm/kup.h | 22 +++++++++++-----------
1 file changed, 11 insertions(+), 11 deletions(-)
diff --git a/arch/powerpc/include/asm/kup.h b/arch/powerpc/include/asm/kup.h
index ec96232529ac..a35ded8bedcd 100644
--- a/arch/powerpc/include/asm/kup.h
+++ b/arch/powerpc/include/asm/kup.h
@@ -96,51 +96,51 @@ static __always_inline void setup_kup(void)
setup_kuap(disable_kuap);
}
-static inline void allow_read_from_user(const void __user *from, unsigned long size)
+static __always_inline void allow_read_from_user(const void __user *from, unsigned long size)
{
barrier_nospec();
allow_user_access(NULL, from, size, KUAP_READ);
}
-static inline void allow_write_to_user(void __user *to, unsigned long size)
+static __always_inline void allow_write_to_user(void __user *to, unsigned long size)
{
allow_user_access(to, NULL, size, KUAP_WRITE);
}
-static inline void allow_read_write_user(void __user *to, const void __user *from,
- unsigned long size)
+static __always_inline void allow_read_write_user(void __user *to, const void __user *from,
+ unsigned long size)
{
barrier_nospec();
allow_user_access(to, from, size, KUAP_READ_WRITE);
}
-static inline void prevent_read_from_user(const void __user *from, unsigned long size)
+static __always_inline void prevent_read_from_user(const void __user *from, unsigned long size)
{
prevent_user_access(NULL, from, size, KUAP_READ);
}
-static inline void prevent_write_to_user(void __user *to, unsigned long size)
+static __always_inline void prevent_write_to_user(void __user *to, unsigned long size)
{
prevent_user_access(to, NULL, size, KUAP_WRITE);
}
-static inline void prevent_read_write_user(void __user *to, const void __user *from,
- unsigned long size)
+static __always_inline void prevent_read_write_user(void __user *to, const void __user *from,
+ unsigned long size)
{
prevent_user_access(to, from, size, KUAP_READ_WRITE);
}
-static inline void prevent_current_access_user(void)
+static __always_inline void prevent_current_access_user(void)
{
prevent_user_access(NULL, NULL, ~0UL, KUAP_CURRENT);
}
-static inline void prevent_current_read_from_user(void)
+static __always_inline void prevent_current_read_from_user(void)
{
prevent_user_access(NULL, NULL, ~0UL, KUAP_CURRENT_READ);
}
-static inline void prevent_current_write_to_user(void)
+static __always_inline void prevent_current_write_to_user(void)
{
prevent_user_access(NULL, NULL, ~0UL, KUAP_CURRENT_WRITE);
}
--
2.25.0
^ permalink raw reply related
* [PATCH 2/5] powerpc/32s: Refactor update of user segment registers
From: Christophe Leroy @ 2021-05-12 8:35 UTC (permalink / raw)
To: Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman
Cc: linuxppc-dev, linux-kernel
In-Reply-To: <e457f345843aa36c6f9ef8e6cb988428ae908df5.1620808468.git.christophe.leroy@csgroup.eu>
KUEP implements the update of user segment registers.
Move it into mmu-hash.h in order to use it from other places.
And inline kuep_lock() and kuep_unlock() and remove kuep.c
inlining kuep_lock() is important for system_call_exception(),
otherwise system_call_exception() has to save into stack the
system call parameters that are used just after, and doing
that takes more instructions than kuep_lock() itself.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
arch/powerpc/include/asm/book3s/32/mmu-hash.h | 27 +++++++++++++
arch/powerpc/include/asm/kup.h | 11 ++++-
arch/powerpc/mm/book3s32/Makefile | 1 -
arch/powerpc/mm/book3s32/kuep.c | 40 -------------------
4 files changed, 36 insertions(+), 43 deletions(-)
delete mode 100644 arch/powerpc/mm/book3s32/kuep.c
diff --git a/arch/powerpc/include/asm/book3s/32/mmu-hash.h b/arch/powerpc/include/asm/book3s/32/mmu-hash.h
index b85f8e114a9c..cc0284bbac86 100644
--- a/arch/powerpc/include/asm/book3s/32/mmu-hash.h
+++ b/arch/powerpc/include/asm/book3s/32/mmu-hash.h
@@ -102,6 +102,33 @@ extern s32 patch__hash_page_B, patch__hash_page_C;
extern s32 patch__flush_hash_A0, patch__flush_hash_A1, patch__flush_hash_A2;
extern s32 patch__flush_hash_B;
+#include <asm/reg.h>
+#include <asm/task_size_32.h>
+
+#define UPDATE_TWO_USER_SEGMENTS(n) do { \
+ if (TASK_SIZE > ((n) << 28)) \
+ mtsr(val1, (n) << 28); \
+ if (TASK_SIZE > (((n) + 1) << 28)) \
+ mtsr(val2, ((n) + 1) << 28); \
+ val1 = (val1 + 0x222) & 0xf0ffffff; \
+ val2 = (val2 + 0x222) & 0xf0ffffff; \
+} while (0)
+
+static __always_inline void update_user_segments(u32 val)
+{
+ int val1 = val;
+ int val2 = (val + 0x111) & 0xf0ffffff;
+
+ UPDATE_TWO_USER_SEGMENTS(0);
+ UPDATE_TWO_USER_SEGMENTS(2);
+ UPDATE_TWO_USER_SEGMENTS(4);
+ UPDATE_TWO_USER_SEGMENTS(6);
+ UPDATE_TWO_USER_SEGMENTS(8);
+ UPDATE_TWO_USER_SEGMENTS(10);
+ UPDATE_TWO_USER_SEGMENTS(12);
+ UPDATE_TWO_USER_SEGMENTS(14);
+}
+
#endif /* !__ASSEMBLY__ */
/* We happily ignore the smaller BATs on 601, we don't actually use
diff --git a/arch/powerpc/include/asm/kup.h b/arch/powerpc/include/asm/kup.h
index a35ded8bedcd..ea83970734cf 100644
--- a/arch/powerpc/include/asm/kup.h
+++ b/arch/powerpc/include/asm/kup.h
@@ -47,8 +47,15 @@ static inline void setup_kuep(bool disabled) { }
#endif /* CONFIG_PPC_KUEP */
#if defined(CONFIG_PPC_KUEP) && defined(CONFIG_PPC_BOOK3S_32)
-void kuep_lock(void);
-void kuep_unlock(void);
+static inline void kuep_lock(void)
+{
+ update_user_segments(mfsr(0) | SR_NX);
+}
+
+static inline void kuep_unlock(void)
+{
+ update_user_segments(mfsr(0) & ~SR_NX);
+}
#else
static inline void kuep_lock(void) { }
static inline void kuep_unlock(void) { }
diff --git a/arch/powerpc/mm/book3s32/Makefile b/arch/powerpc/mm/book3s32/Makefile
index 7f0c8a78ba0c..446d9de88ce4 100644
--- a/arch/powerpc/mm/book3s32/Makefile
+++ b/arch/powerpc/mm/book3s32/Makefile
@@ -9,4 +9,3 @@ endif
obj-y += mmu.o mmu_context.o
obj-$(CONFIG_PPC_BOOK3S_603) += nohash_low.o
obj-$(CONFIG_PPC_BOOK3S_604) += hash_low.o tlb.o
-obj-$(CONFIG_PPC_KUEP) += kuep.o
diff --git a/arch/powerpc/mm/book3s32/kuep.c b/arch/powerpc/mm/book3s32/kuep.c
deleted file mode 100644
index 8ed1b8634839..000000000000
--- a/arch/powerpc/mm/book3s32/kuep.c
+++ /dev/null
@@ -1,40 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-or-later
-
-#include <asm/kup.h>
-#include <asm/reg.h>
-#include <asm/task_size_32.h>
-#include <asm/mmu.h>
-
-#define KUEP_UPDATE_TWO_USER_SEGMENTS(n) do { \
- if (TASK_SIZE > ((n) << 28)) \
- mtsr(val1, (n) << 28); \
- if (TASK_SIZE > (((n) + 1) << 28)) \
- mtsr(val2, ((n) + 1) << 28); \
- val1 = (val1 + 0x222) & 0xf0ffffff; \
- val2 = (val2 + 0x222) & 0xf0ffffff; \
-} while (0)
-
-static __always_inline void kuep_update(u32 val)
-{
- int val1 = val;
- int val2 = (val + 0x111) & 0xf0ffffff;
-
- KUEP_UPDATE_TWO_USER_SEGMENTS(0);
- KUEP_UPDATE_TWO_USER_SEGMENTS(2);
- KUEP_UPDATE_TWO_USER_SEGMENTS(4);
- KUEP_UPDATE_TWO_USER_SEGMENTS(6);
- KUEP_UPDATE_TWO_USER_SEGMENTS(8);
- KUEP_UPDATE_TWO_USER_SEGMENTS(10);
- KUEP_UPDATE_TWO_USER_SEGMENTS(12);
- KUEP_UPDATE_TWO_USER_SEGMENTS(14);
-}
-
-void kuep_lock(void)
-{
- kuep_update(mfsr(0) | SR_NX);
-}
-
-void kuep_unlock(void)
-{
- kuep_update(mfsr(0) & ~SR_NX);
-}
--
2.25.0
^ permalink raw reply related
* [PATCH 3/5] powerpc/kuap: Rework Kernel Userspace Access Protection on book3s/32
From: Christophe Leroy @ 2021-05-12 8:35 UTC (permalink / raw)
To: Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman
Cc: linuxppc-dev, linux-kernel
In-Reply-To: <e457f345843aa36c6f9ef8e6cb988428ae908df5.1620808468.git.christophe.leroy@csgroup.eu>
On book3s/32, KUAP is provided by toggling Ks bit in segment registers.
One segment registers addresses 256M of virtual memory.
At the time being, KUAP implements a complex logic to apply the
unlock/lock on the exact number of segments covering the user range
to access, with saving the boundaries of the range of segments in
a member of thread struct.
But most if not all user accesses are within a single segment.
Rework KUAP with a different approach:
- Open only one segment, the one corresponding to the starting
address of the range to be accessed.
- If a second segment is involved, it will generate a page fault. The
segment will then be open by the page fault handler.
The kuap member of thread struct will now contain:
- The start address of the current on going user access, that will be
used to know which segment to lock at the end of the user access.
- ~0 when no user access is open
- ~1 when additionnal segments are opened by a page fault.
Then, at lock time
- When only one segment is open, close it.
- When several segments are open, close all user segments.
Almost 100% of the time, only one segment will be involved.
In interrupts, inline the function that unlock/lock all segments,
because not inlining them implies a lot of register save/restore.
With the patch, writing value 128 in userspace in perf_copy_attr() is
done with 16 instructions:
3890: 93 82 04 dc stw r28,1244(r2)
3894: 7d 20 e5 26 mfsrin r9,r28
3898: 55 29 00 80 rlwinm r9,r9,0,2,0
389c: 7d 20 e1 e4 mtsrin r9,r28
38a0: 4c 00 01 2c isync
38a4: 39 20 00 80 li r9,128
38a8: 91 3c 00 00 stw r9,0(r28)
38ac: 81 42 04 dc lwz r10,1244(r2)
38b0: 39 00 ff ff li r8,-1
38b4: 91 02 04 dc stw r8,1244(r2)
38b8: 2c 0a ff fe cmpwi r10,-2
38bc: 41 82 00 88 beq 3944 <perf_copy_attr+0x36c>
38c0: 7d 20 55 26 mfsrin r9,r10
38c4: 65 29 40 00 oris r9,r9,16384
38c8: 7d 20 51 e4 mtsrin r9,r10
38cc: 4c 00 01 2c isync
...
3944: 48 00 00 01 bl 3944 <perf_copy_attr+0x36c>
3944: R_PPC_REL24 kuap_lock_all_ool
Before the patch it was 118 instructions. In reality only 42 are
executed in most cases, but GCC is not able to see that a properly
aligned user access cannot involve more than one segment.
5060: 39 1d 00 04 addi r8,r29,4
5064: 3d 20 b0 00 lis r9,-20480
5068: 7c 08 48 40 cmplw r8,r9
506c: 40 81 00 08 ble 5074 <perf_copy_attr+0x2cc>
5070: 3d 00 b0 00 lis r8,-20480
5074: 39 28 ff ff addi r9,r8,-1
5078: 57 aa 00 06 rlwinm r10,r29,0,0,3
507c: 55 29 27 3e rlwinm r9,r9,4,28,31
5080: 39 29 00 01 addi r9,r9,1
5084: 7d 29 53 78 or r9,r9,r10
5088: 91 22 04 dc stw r9,1244(r2)
508c: 7d 20 ed 26 mfsrin r9,r29
5090: 55 29 00 80 rlwinm r9,r9,0,2,0
5094: 7c 08 50 40 cmplw r8,r10
5098: 40 81 00 c0 ble 5158 <perf_copy_attr+0x3b0>
509c: 7d 46 50 f8 not r6,r10
50a0: 7c c6 42 14 add r6,r6,r8
50a4: 54 c6 27 be rlwinm r6,r6,4,30,31
50a8: 7d 20 51 e4 mtsrin r9,r10
50ac: 3c ea 10 00 addis r7,r10,4096
50b0: 39 29 01 11 addi r9,r9,273
50b4: 7f 88 38 40 cmplw cr7,r8,r7
50b8: 55 29 02 06 rlwinm r9,r9,0,8,3
50bc: 40 9d 00 9c ble cr7,5158 <perf_copy_attr+0x3b0>
50c0: 2f 86 00 00 cmpwi cr7,r6,0
50c4: 41 9e 00 4c beq cr7,5110 <perf_copy_attr+0x368>
50c8: 2f 86 00 01 cmpwi cr7,r6,1
50cc: 41 9e 00 2c beq cr7,50f8 <perf_copy_attr+0x350>
50d0: 2f 86 00 02 cmpwi cr7,r6,2
50d4: 41 9e 00 14 beq cr7,50e8 <perf_copy_attr+0x340>
50d8: 7d 20 39 e4 mtsrin r9,r7
50dc: 39 29 01 11 addi r9,r9,273
50e0: 3c e7 10 00 addis r7,r7,4096
50e4: 55 29 02 06 rlwinm r9,r9,0,8,3
50e8: 7d 20 39 e4 mtsrin r9,r7
50ec: 39 29 01 11 addi r9,r9,273
50f0: 3c e7 10 00 addis r7,r7,4096
50f4: 55 29 02 06 rlwinm r9,r9,0,8,3
50f8: 7d 20 39 e4 mtsrin r9,r7
50fc: 3c e7 10 00 addis r7,r7,4096
5100: 39 29 01 11 addi r9,r9,273
5104: 7f 88 38 40 cmplw cr7,r8,r7
5108: 55 29 02 06 rlwinm r9,r9,0,8,3
510c: 40 9d 00 4c ble cr7,5158 <perf_copy_attr+0x3b0>
5110: 7d 20 39 e4 mtsrin r9,r7
5114: 39 29 01 11 addi r9,r9,273
5118: 3c c7 10 00 addis r6,r7,4096
511c: 55 29 02 06 rlwinm r9,r9,0,8,3
5120: 7d 20 31 e4 mtsrin r9,r6
5124: 39 29 01 11 addi r9,r9,273
5128: 3c c6 10 00 addis r6,r6,4096
512c: 55 29 02 06 rlwinm r9,r9,0,8,3
5130: 7d 20 31 e4 mtsrin r9,r6
5134: 39 29 01 11 addi r9,r9,273
5138: 3c c7 30 00 addis r6,r7,12288
513c: 55 29 02 06 rlwinm r9,r9,0,8,3
5140: 7d 20 31 e4 mtsrin r9,r6
5144: 3c e7 40 00 addis r7,r7,16384
5148: 39 29 01 11 addi r9,r9,273
514c: 7f 88 38 40 cmplw cr7,r8,r7
5150: 55 29 02 06 rlwinm r9,r9,0,8,3
5154: 41 9d ff bc bgt cr7,5110 <perf_copy_attr+0x368>
5158: 4c 00 01 2c isync
515c: 39 20 00 80 li r9,128
5160: 91 3d 00 00 stw r9,0(r29)
5164: 38 e0 00 00 li r7,0
5168: 90 e2 04 dc stw r7,1244(r2)
516c: 7d 20 ed 26 mfsrin r9,r29
5170: 65 29 40 00 oris r9,r9,16384
5174: 40 81 00 c0 ble 5234 <perf_copy_attr+0x48c>
5178: 7d 47 50 f8 not r7,r10
517c: 7c e7 42 14 add r7,r7,r8
5180: 54 e7 27 be rlwinm r7,r7,4,30,31
5184: 7d 20 51 e4 mtsrin r9,r10
5188: 3d 4a 10 00 addis r10,r10,4096
518c: 39 29 01 11 addi r9,r9,273
5190: 7c 08 50 40 cmplw r8,r10
5194: 55 29 02 06 rlwinm r9,r9,0,8,3
5198: 40 81 00 9c ble 5234 <perf_copy_attr+0x48c>
519c: 2c 07 00 00 cmpwi r7,0
51a0: 41 82 00 4c beq 51ec <perf_copy_attr+0x444>
51a4: 2c 07 00 01 cmpwi r7,1
51a8: 41 82 00 2c beq 51d4 <perf_copy_attr+0x42c>
51ac: 2c 07 00 02 cmpwi r7,2
51b0: 41 82 00 14 beq 51c4 <perf_copy_attr+0x41c>
51b4: 7d 20 51 e4 mtsrin r9,r10
51b8: 39 29 01 11 addi r9,r9,273
51bc: 3d 4a 10 00 addis r10,r10,4096
51c0: 55 29 02 06 rlwinm r9,r9,0,8,3
51c4: 7d 20 51 e4 mtsrin r9,r10
51c8: 39 29 01 11 addi r9,r9,273
51cc: 3d 4a 10 00 addis r10,r10,4096
51d0: 55 29 02 06 rlwinm r9,r9,0,8,3
51d4: 7d 20 51 e4 mtsrin r9,r10
51d8: 3d 4a 10 00 addis r10,r10,4096
51dc: 39 29 01 11 addi r9,r9,273
51e0: 7c 08 50 40 cmplw r8,r10
51e4: 55 29 02 06 rlwinm r9,r9,0,8,3
51e8: 40 81 00 4c ble 5234 <perf_copy_attr+0x48c>
51ec: 7d 20 51 e4 mtsrin r9,r10
51f0: 39 29 01 11 addi r9,r9,273
51f4: 3c ea 10 00 addis r7,r10,4096
51f8: 55 29 02 06 rlwinm r9,r9,0,8,3
51fc: 7d 20 39 e4 mtsrin r9,r7
5200: 39 29 01 11 addi r9,r9,273
5204: 3c e7 10 00 addis r7,r7,4096
5208: 55 29 02 06 rlwinm r9,r9,0,8,3
520c: 7d 20 39 e4 mtsrin r9,r7
5210: 39 29 01 11 addi r9,r9,273
5214: 3c ea 30 00 addis r7,r10,12288
5218: 55 29 02 06 rlwinm r9,r9,0,8,3
521c: 7d 20 39 e4 mtsrin r9,r7
5220: 3d 4a 40 00 addis r10,r10,16384
5224: 39 29 01 11 addi r9,r9,273
5228: 7c 08 50 40 cmplw r8,r10
522c: 55 29 02 06 rlwinm r9,r9,0,8,3
5230: 41 81 ff bc bgt 51ec <perf_copy_attr+0x444>
5234: 4c 00 01 2c isync
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
arch/powerpc/include/asm/book3s/32/kup.h | 148 ++++++++++++-----------
arch/powerpc/include/asm/processor.h | 10 +-
arch/powerpc/kernel/process.c | 3 +
arch/powerpc/mm/book3s32/Makefile | 1 +
arch/powerpc/mm/book3s32/kuap.c | 14 +++
5 files changed, 106 insertions(+), 70 deletions(-)
create mode 100644 arch/powerpc/mm/book3s32/kuap.c
diff --git a/arch/powerpc/include/asm/book3s/32/kup.h b/arch/powerpc/include/asm/book3s/32/kup.h
index 1670dfe9d4f1..c67b91c1ca80 100644
--- a/arch/powerpc/include/asm/book3s/32/kup.h
+++ b/arch/powerpc/include/asm/book3s/32/kup.h
@@ -11,31 +11,66 @@
#include <linux/sched.h>
-static inline void kuap_update_sr(u32 sr, u32 addr, u32 end)
-{
- addr &= 0xf0000000; /* align addr to start of segment */
- barrier(); /* make sure thread.kuap is updated before playing with SRs */
- while (addr < end) {
- mtsr(sr, addr);
- sr += 0x111; /* next VSID */
- sr &= 0xf0ffffff; /* clear VSID overflow */
- addr += 0x10000000; /* address of next segment */
- }
+#define KUAP_NONE (~0UL)
+#define KUAP_ALL (~1UL)
+
+static inline void kuap_lock_one(unsigned long addr)
+{
+ mtsr(mfsr(addr) | SR_KS, addr);
+ isync(); /* Context sync required after mtsr() */
+}
+
+static inline void kuap_unlock_one(unsigned long addr)
+{
+ mtsr(mfsr(addr) & ~SR_KS, addr);
+ isync(); /* Context sync required after mtsr() */
+}
+
+static inline void kuap_lock_all(void)
+{
+ update_user_segments(mfsr(0) | SR_KS);
isync(); /* Context sync required after mtsr() */
}
+static inline void kuap_unlock_all(void)
+{
+ update_user_segments(mfsr(0) & ~SR_KS);
+ isync(); /* Context sync required after mtsr() */
+}
+
+void kuap_lock_all_ool(void);
+void kuap_unlock_all_ool(void);
+
+static inline void kuap_lock(unsigned long addr, bool ool)
+{
+ if (likely(addr != KUAP_ALL))
+ kuap_lock_one(addr);
+ else if (!ool)
+ kuap_lock_all();
+ else
+ kuap_lock_all_ool();
+}
+
+static inline void kuap_unlock(unsigned long addr, bool ool)
+{
+ if (likely(addr != KUAP_ALL))
+ kuap_unlock_one(addr);
+ else if (!ool)
+ kuap_unlock_all();
+ else
+ kuap_unlock_all_ool();
+}
+
static inline void kuap_save_and_lock(struct pt_regs *regs)
{
unsigned long kuap = current->thread.kuap;
- u32 addr = kuap & 0xf0000000;
- u32 end = kuap << 28;
regs->kuap = kuap;
- if (unlikely(!kuap))
+ if (unlikely(kuap == KUAP_NONE))
return;
- current->thread.kuap = 0;
- kuap_update_sr(mfsr(addr) | SR_KS, addr, end); /* Set Ks */
+ current->thread.kuap = KUAP_NONE;
+ kuap_lock(kuap, false);
}
static inline void kuap_user_restore(struct pt_regs *regs)
@@ -44,22 +79,16 @@ static inline void kuap_user_restore(struct pt_regs *regs)
static inline void kuap_kernel_restore(struct pt_regs *regs, unsigned long kuap)
{
- u32 addr = regs->kuap & 0xf0000000;
- u32 end = regs->kuap << 28;
-
current->thread.kuap = regs->kuap;
- if (unlikely(regs->kuap == kuap))
- return;
-
- kuap_update_sr(mfsr(addr) & ~SR_KS, addr, end); /* Clear Ks */
+ kuap_unlock(regs->kuap, false);
}
static inline unsigned long kuap_get_and_assert_locked(void)
{
unsigned long kuap = current->thread.kuap;
- WARN_ON_ONCE(IS_ENABLED(CONFIG_PPC_KUAP_DEBUG) && kuap != 0);
+ WARN_ON_ONCE(IS_ENABLED(CONFIG_PPC_KUAP_DEBUG) && kuap != KUAP_NONE);
return kuap;
}
@@ -72,84 +101,65 @@ static inline void kuap_assert_locked(void)
static __always_inline void allow_user_access(void __user *to, const void __user *from,
u32 size, unsigned long dir)
{
- u32 addr, end;
-
BUILD_BUG_ON(!__builtin_constant_p(dir));
BUILD_BUG_ON(dir & ~KUAP_READ_WRITE);
-
if (!(dir & KUAP_WRITE))
return;
- addr = (__force u32)to;
-
- if (unlikely(addr >= TASK_SIZE || !size))
- return;
-
- end = min(addr + size, TASK_SIZE);
-
- current->thread.kuap = (addr & 0xf0000000) | ((((end - 1) >> 28) + 1) & 0xf);
- kuap_update_sr(mfsr(addr) & ~SR_KS, addr, end); /* Clear Ks */
+ current->thread.kuap = (__force u32)to;
+ kuap_unlock_one((__force u32)to);
}
static __always_inline void prevent_user_access(void __user *to, const void __user *from,
u32 size, unsigned long dir)
{
- u32 addr, end;
+ u32 kuap = current->thread.kuap;
BUILD_BUG_ON(!__builtin_constant_p(dir));
-
- if (dir & KUAP_CURRENT_WRITE) {
- u32 kuap = current->thread.kuap;
-
- if (unlikely(!kuap))
- return;
-
- addr = kuap & 0xf0000000;
- end = kuap << 28;
- } else if (dir & KUAP_WRITE) {
- addr = (__force u32)to;
- end = min(addr + size, TASK_SIZE);
-
- if (unlikely(addr >= TASK_SIZE || !size))
- return;
- } else {
+ if (!(dir & KUAP_WRITE))
return;
- }
- current->thread.kuap = 0;
- kuap_update_sr(mfsr(addr) | SR_KS, addr, end); /* set Ks */
+ current->thread.kuap = KUAP_NONE;
+ kuap_lock(kuap, true);
}
static inline unsigned long prevent_user_access_return(void)
{
unsigned long flags = current->thread.kuap;
- unsigned long addr = flags & 0xf0000000;
- unsigned long end = flags << 28;
- void __user *to = (__force void __user *)addr;
- if (flags)
- prevent_user_access(to, to, end - addr, KUAP_READ_WRITE);
+ if (flags != KUAP_NONE) {
+ current->thread.kuap = KUAP_NONE;
+ kuap_lock(flags, true);
+ }
return flags;
}
static inline void restore_user_access(unsigned long flags)
{
- unsigned long addr = flags & 0xf0000000;
- unsigned long end = flags << 28;
- void __user *to = (__force void __user *)addr;
-
- if (flags)
- allow_user_access(to, to, end - addr, KUAP_READ_WRITE);
+ if (flags != KUAP_NONE) {
+ current->thread.kuap = flags;
+ kuap_unlock(flags, true);
+ }
}
static inline bool
bad_kuap_fault(struct pt_regs *regs, unsigned long address, bool is_write)
{
- unsigned long begin = regs->kuap & 0xf0000000;
- unsigned long end = regs->kuap << 28;
+ unsigned long kuap = regs->kuap;
+
+ if (!is_write)
+ return false;
+ if (kuap == KUAP_NONE)
+ return true;
+ if (kuap == KUAP_ALL)
+ return false;
+
+ /* If faulting address doesn't match unlocked segment, unlock all */
+ if ((kuap ^ address) & 0xf0000000)
+ regs->kuap = KUAP_ALL;
- return is_write && (address < begin || address >= end);
+ return false;
}
#endif /* CONFIG_PPC_KUAP */
diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h
index 7bf8a15af224..aeb1a35163d1 100644
--- a/arch/powerpc/include/asm/processor.h
+++ b/arch/powerpc/include/asm/processor.h
@@ -276,7 +276,15 @@ struct thread_struct {
#define SPEFSCR_INIT
#endif
-#ifdef CONFIG_PPC32
+#if defined(CONFIG_PPC_BOOK3S_32) && defined(CONFIG_PPC_KUAP)
+#define INIT_THREAD { \
+ .ksp = INIT_SP, \
+ .pgdir = swapper_pg_dir, \
+ .kuap = ~0UL, /* KUAP_NONE */ \
+ .fpexc_mode = MSR_FE0 | MSR_FE1, \
+ SPEFSCR_INIT \
+}
+#elif defined(CONFIG_PPC32)
#define INIT_THREAD { \
.ksp = INIT_SP, \
.pgdir = swapper_pg_dir, \
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 89e34aa273e2..c6d21604457d 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1736,6 +1736,9 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
#ifdef CONFIG_ALTIVEC
p->thread.vr_save_area = NULL;
#endif
+#if defined(CONFIG_PPC_BOOK3S_32) && defined(CONFIG_PPC_KUAP)
+ p->thread.kuap = KUAP_NONE;
+#endif
setup_ksp_vsid(p, sp);
diff --git a/arch/powerpc/mm/book3s32/Makefile b/arch/powerpc/mm/book3s32/Makefile
index 446d9de88ce4..50dd8f6bdf46 100644
--- a/arch/powerpc/mm/book3s32/Makefile
+++ b/arch/powerpc/mm/book3s32/Makefile
@@ -9,3 +9,4 @@ endif
obj-y += mmu.o mmu_context.o
obj-$(CONFIG_PPC_BOOK3S_603) += nohash_low.o
obj-$(CONFIG_PPC_BOOK3S_604) += hash_low.o tlb.o
+obj-$(CONFIG_PPC_KUAP) += kuap.o
diff --git a/arch/powerpc/mm/book3s32/kuap.c b/arch/powerpc/mm/book3s32/kuap.c
new file mode 100644
index 000000000000..5b01e746a90f
--- /dev/null
+++ b/arch/powerpc/mm/book3s32/kuap.c
@@ -0,0 +1,14 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <asm/kup.h>
+
+void kuap_lock_all_ool(void)
+{
+ kuap_lock_all();
+}
+
+void kuap_unlock_all_ool(void)
+{
+ kuap_unlock_all();
+}
+
--
2.25.0
^ permalink raw reply related
* [PATCH 4/5] powerpc/kuap: Remove KUAP_CURRENT_XXX
From: Christophe Leroy @ 2021-05-12 8:35 UTC (permalink / raw)
To: Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman
Cc: linuxppc-dev, linux-kernel
In-Reply-To: <e457f345843aa36c6f9ef8e6cb988428ae908df5.1620808468.git.christophe.leroy@csgroup.eu>
book3s/32 was the only user of KUAP_CURRENT_XXX.
After rework of book3s/32 KUAP, it is not used anymore.
Remove it.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
arch/powerpc/include/asm/book3s/32/kup.h | 1 -
arch/powerpc/include/asm/kup.h | 14 +++-----------
2 files changed, 3 insertions(+), 12 deletions(-)
diff --git a/arch/powerpc/include/asm/book3s/32/kup.h b/arch/powerpc/include/asm/book3s/32/kup.h
index c67b91c1ca80..7b88f7bdd90f 100644
--- a/arch/powerpc/include/asm/book3s/32/kup.h
+++ b/arch/powerpc/include/asm/book3s/32/kup.h
@@ -102,7 +102,6 @@ static __always_inline void allow_user_access(void __user *to, const void __user
u32 size, unsigned long dir)
{
BUILD_BUG_ON(!__builtin_constant_p(dir));
- BUILD_BUG_ON(dir & ~KUAP_READ_WRITE);
if (!(dir & KUAP_WRITE))
return;
diff --git a/arch/powerpc/include/asm/kup.h b/arch/powerpc/include/asm/kup.h
index ea83970734cf..aa93eb4e3be5 100644
--- a/arch/powerpc/include/asm/kup.h
+++ b/arch/powerpc/include/asm/kup.h
@@ -5,14 +5,6 @@
#define KUAP_READ 1
#define KUAP_WRITE 2
#define KUAP_READ_WRITE (KUAP_READ | KUAP_WRITE)
-/*
- * For prevent_user_access() only.
- * Use the current saved situation instead of the to/from/size params.
- * Used on book3s/32
- */
-#define KUAP_CURRENT_READ 4
-#define KUAP_CURRENT_WRITE 8
-#define KUAP_CURRENT (KUAP_CURRENT_READ | KUAP_CURRENT_WRITE)
#ifdef CONFIG_PPC_BOOK3S_64
#include <asm/book3s/64/kup.h>
@@ -139,17 +131,17 @@ static __always_inline void prevent_read_write_user(void __user *to, const void
static __always_inline void prevent_current_access_user(void)
{
- prevent_user_access(NULL, NULL, ~0UL, KUAP_CURRENT);
+ prevent_user_access(NULL, NULL, ~0UL, KUAP_READ_WRITE);
}
static __always_inline void prevent_current_read_from_user(void)
{
- prevent_user_access(NULL, NULL, ~0UL, KUAP_CURRENT_READ);
+ prevent_user_access(NULL, NULL, ~0UL, KUAP_READ);
}
static __always_inline void prevent_current_write_to_user(void)
{
- prevent_user_access(NULL, NULL, ~0UL, KUAP_CURRENT_WRITE);
+ prevent_user_access(NULL, NULL, ~0UL, KUAP_WRITE);
}
#endif /* !__ASSEMBLY__ */
--
2.25.0
^ permalink raw reply related
* [PATCH 5/5] powerpc/kuap: Remove to/from/size parameters of prevent_user_access()
From: Christophe Leroy @ 2021-05-12 8:35 UTC (permalink / raw)
To: Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman
Cc: linuxppc-dev, linux-kernel
In-Reply-To: <e457f345843aa36c6f9ef8e6cb988428ae908df5.1620808468.git.christophe.leroy@csgroup.eu>
prevent_user_access() doesn't use anymore to/from/size parameters.
Remove them.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
arch/powerpc/include/asm/book3s/32/kup.h | 3 +--
arch/powerpc/include/asm/book3s/64/kup.h | 3 +--
arch/powerpc/include/asm/kup.h | 15 +++++++--------
arch/powerpc/include/asm/nohash/32/kup-8xx.h | 3 +--
4 files changed, 10 insertions(+), 14 deletions(-)
diff --git a/arch/powerpc/include/asm/book3s/32/kup.h b/arch/powerpc/include/asm/book3s/32/kup.h
index 7b88f7bdd90f..8149dae165ce 100644
--- a/arch/powerpc/include/asm/book3s/32/kup.h
+++ b/arch/powerpc/include/asm/book3s/32/kup.h
@@ -109,8 +109,7 @@ static __always_inline void allow_user_access(void __user *to, const void __user
kuap_unlock_one((__force u32)to);
}
-static __always_inline void prevent_user_access(void __user *to, const void __user *from,
- u32 size, unsigned long dir)
+static __always_inline void prevent_user_access(unsigned long dir)
{
u32 kuap = current->thread.kuap;
diff --git a/arch/powerpc/include/asm/book3s/64/kup.h b/arch/powerpc/include/asm/book3s/64/kup.h
index 9700da3a4093..a1cc73a88710 100644
--- a/arch/powerpc/include/asm/book3s/64/kup.h
+++ b/arch/powerpc/include/asm/book3s/64/kup.h
@@ -398,8 +398,7 @@ static __always_inline void allow_user_access(void __user *to, const void __user
#endif /* !CONFIG_PPC_KUAP */
-static inline void prevent_user_access(void __user *to, const void __user *from,
- unsigned long size, unsigned long dir)
+static inline void prevent_user_access(unsigned long dir)
{
set_kuap(AMR_KUAP_BLOCKED);
if (static_branch_unlikely(&uaccess_flush_key))
diff --git a/arch/powerpc/include/asm/kup.h b/arch/powerpc/include/asm/kup.h
index aa93eb4e3be5..341a064a7bfa 100644
--- a/arch/powerpc/include/asm/kup.h
+++ b/arch/powerpc/include/asm/kup.h
@@ -82,8 +82,7 @@ static inline unsigned long kuap_get_and_assert_locked(void)
#ifndef CONFIG_PPC_BOOK3S_64
static inline void allow_user_access(void __user *to, const void __user *from,
unsigned long size, unsigned long dir) { }
-static inline void prevent_user_access(void __user *to, const void __user *from,
- unsigned long size, unsigned long dir) { }
+static inline void prevent_user_access(unsigned long dir) { }
static inline unsigned long prevent_user_access_return(void) { return 0UL; }
static inline void restore_user_access(unsigned long flags) { }
#endif /* CONFIG_PPC_BOOK3S_64 */
@@ -115,33 +114,33 @@ static __always_inline void allow_read_write_user(void __user *to, const void __
static __always_inline void prevent_read_from_user(const void __user *from, unsigned long size)
{
- prevent_user_access(NULL, from, size, KUAP_READ);
+ prevent_user_access(KUAP_READ);
}
static __always_inline void prevent_write_to_user(void __user *to, unsigned long size)
{
- prevent_user_access(to, NULL, size, KUAP_WRITE);
+ prevent_user_access(KUAP_WRITE);
}
static __always_inline void prevent_read_write_user(void __user *to, const void __user *from,
unsigned long size)
{
- prevent_user_access(to, from, size, KUAP_READ_WRITE);
+ prevent_user_access(KUAP_READ_WRITE);
}
static __always_inline void prevent_current_access_user(void)
{
- prevent_user_access(NULL, NULL, ~0UL, KUAP_READ_WRITE);
+ prevent_user_access(KUAP_READ_WRITE);
}
static __always_inline void prevent_current_read_from_user(void)
{
- prevent_user_access(NULL, NULL, ~0UL, KUAP_READ);
+ prevent_user_access(KUAP_READ);
}
static __always_inline void prevent_current_write_to_user(void)
{
- prevent_user_access(NULL, NULL, ~0UL, KUAP_WRITE);
+ prevent_user_access(KUAP_WRITE);
}
#endif /* !__ASSEMBLY__ */
diff --git a/arch/powerpc/include/asm/nohash/32/kup-8xx.h b/arch/powerpc/include/asm/nohash/32/kup-8xx.h
index 295ef5639609..61333e3b5d2b 100644
--- a/arch/powerpc/include/asm/nohash/32/kup-8xx.h
+++ b/arch/powerpc/include/asm/nohash/32/kup-8xx.h
@@ -48,8 +48,7 @@ static inline void allow_user_access(void __user *to, const void __user *from,
mtspr(SPRN_MD_AP, MD_APG_INIT);
}
-static inline void prevent_user_access(void __user *to, const void __user *from,
- unsigned long size, unsigned long dir)
+static inline void prevent_user_access(unsigned long dir)
{
mtspr(SPRN_MD_AP, MD_APG_KUAP);
}
--
2.25.0
^ permalink raw reply related
* Re: [PATCH v3 0/4] P2040/P2041 i2c recovery erratum
From: Joakim Tjernlund @ 2021-05-12 8:57 UTC (permalink / raw)
To: andy.shevchenko@gmail.com, andriy.shevchenko@linux.intel.com,
mpe@ellerman.id.au, Chris.Packham@alliedtelesis.co.nz,
wsa@kernel.org, robh+dt@kernel.org
Cc: devicetree@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org
In-Reply-To: <ec3cdcc8-5869-9e7d-30c0-59ff4ec67a58@alliedtelesis.co.nz>
On Wed, 2021-05-12 at 01:48 +0000, Chris Packham wrote:
> On 12/05/21 10:10 am, Joakim Tjernlund wrote:
> > On Wed, 2021-05-12 at 09:20 +1200, Chris Packham wrote:
> > > The P2040/P2041 has an erratum where the i2c recovery scheme
> > > documented in the reference manual (and currently implemented
> > > in the i2c-mpc.c driver) does not work. The errata document
> > > provides an alternative that does work. This series implements
> > > that alternative and uses a property in the devicetree to
> > > decide when the alternative mechanism is needed.
> > >
> > > Chris Packham (4):
> > > dt-bindings: i2c: mpc: Add fsl,i2c-erratum-a004447 flag
> > > powerpc/fsl: set fsl,i2c-erratum-a004447 flag for P2041 i2c
> > > controllers
> > > powerpc/fsl: set fsl,i2c-erratum-a004447 flag for P1010 i2c
> > > controllers
> > > i2c: mpc: implement erratum A-004447 workaround
> > >
> > > .../devicetree/bindings/i2c/i2c-mpc.yaml | 7 ++
> > > arch/powerpc/boot/dts/fsl/p1010si-post.dtsi | 8 ++
> > > arch/powerpc/boot/dts/fsl/p2041si-post.dtsi | 16 ++++
> > > drivers/i2c/busses/i2c-mpc.c | 81 ++++++++++++++++++-
> > > 4 files changed, 110 insertions(+), 2 deletions(-)
> > >
> > This now reminds me about the current I2C reset procedure, it didn't work for us and I came up with this one:
> > https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.spinics.net%2Flists%2Flinux-i2c%2Fmsg29490.html&data=04%7C01%7CJoakim.Tjernlund%40infinera.com%7Cb85a6e9c3c8b469572da08d914e816b5%7C285643de5f5b4b03a1530ae2dc8aaf77%7C1%7C0%7C637563809322419998%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=4cwujNmAVlBa08Tt79hLYGJfJtn7wdz1Kgz0eW2VX9U%3D&reserved=0
> > it never got in but we are still using it.
>
> For those reading along the v2 mentioned in that thread was posted as
> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Flinux-i2c%2F20170511122033.22471-1-joakim.tjernlund%40infinera.com%2F&data=04%7C01%7CJoakim.Tjernlund%40infinera.com%7Cb85a6e9c3c8b469572da08d914e816b5%7C285643de5f5b4b03a1530ae2dc8aaf77%7C1%7C0%7C637563809322419998%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=YDTX5L6J2ocHep5XutVN46jUpvJj7h1aDbHHwMqlrAs%3D&reserved=0
> there was a bit of discussion but it seemed to die out without reaching
> a conclusion.
>
> The i2c-mpc driver is now using the generic recovery mechanism so that
> addresses one bit of feedback from the original thread.
>
> I do wonder if the reason the recovery wasn't working for your case was
> because of the erratum. Do you happen to remember which SoC your issue
> was on?
It could only be P2010 or MPC8321, I think it was MPC8321, you could try my solution on your
CPU if you want to make sure.
>
> I've been doing my recent work with a P2040 and prior to that I did test
> out the recovery on a T2081 (which isn't documented to have this
> erratum) when I was re-working the driver. The "new" recovery actually
> seems better but I don't have a reliably faulty i2c device so that's
> only based on me writing some code to manually trigger the recovery
> (using the snippet below) and observing it with an oscilloscope.
You don't need a faulty device, just an aborted I2C read/write op.
You could force one such I2C op. by py pulling down the clock/SDA in the middle of a byte transfer.
Jocke
^ permalink raw reply
* [PATCH] sched: Initialize the idle task with preemption disabled
From: Valentin Schneider @ 2021-05-12 9:46 UTC (permalink / raw)
To: linux-kernel, linux-alpha, linux-snps-arc, linux-arm-kernel,
linux-csky, linux-ia64, linux-mips, openrisc, linux-parisc,
linuxppc-dev, linux-riscv, linux-s390, linux-sh, sparclinux,
linux-xtensa, linux-arch
Cc: Juri Lelli, Vincent Guittot, yejune.deng, peterz, Steven Rostedt,
Dietmar Eggemann, tglx, bristot, mingo
As pointed out by commit
de9b8f5dcbd9 ("sched: Fix crash trying to dequeue/enqueue the idle thread")
init_idle() can and will be invoked more than once on the same idle
task. At boot time, it is invoked for the boot CPU thread by
sched_init(). Then smp_init() creates the threads for all the secondary
CPUs and invokes init_idle() on them.
As the hotplug machinery brings the secondaries to life, it will issue
calls to idle_thread_get(), which itself invokes init_idle() yet again.
In this case it's invoked twice more per secondary: at _cpu_up(), and at
bringup_cpu().
Given smp_init() already initializes the idle tasks for all *possible*
CPUs, no further initialization should be required. Now, removing
init_idle() from idle_thread_get() exposes some interesting expectations
with regards to the idle task's preempt_count: the secondary startup always
issues a preempt_disable(), requiring some reset of the preempt count to 0
between hot-unplug and hotplug, which is currently served by
idle_thread_get() -> idle_init().
Given the idle task is supposed to have preemption disabled once and never
see it re-enabled, it seems that what we actually want is to initialize its
preempt_count to PREEMPT_DISABLED and leave it there. Do that, and remove
init_idle() from idle_thread_get().
Secondary startups were patched via coccinelle:
@begone@
@@
-preempt_disable();
...
cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
---
arch/alpha/kernel/smp.c | 1 -
arch/arc/kernel/smp.c | 1 -
arch/arm/kernel/smp.c | 1 -
arch/arm64/include/asm/preempt.h | 2 +-
arch/arm64/kernel/smp.c | 1 -
arch/csky/kernel/smp.c | 1 -
arch/ia64/kernel/smpboot.c | 1 -
arch/mips/kernel/smp.c | 1 -
arch/openrisc/kernel/smp.c | 2 --
arch/parisc/kernel/smp.c | 1 -
arch/powerpc/kernel/smp.c | 1 -
arch/riscv/kernel/smpboot.c | 1 -
arch/s390/include/asm/preempt.h | 4 ++--
arch/s390/kernel/smp.c | 1 -
arch/sh/kernel/smp.c | 2 --
arch/sparc/kernel/smp_32.c | 1 -
arch/sparc/kernel/smp_64.c | 3 ---
arch/x86/include/asm/preempt.h | 2 +-
arch/x86/kernel/smpboot.c | 1 -
arch/xtensa/kernel/smp.c | 1 -
include/asm-generic/preempt.h | 2 +-
init/main.c | 6 +-----
kernel/fork.c | 2 +-
kernel/sched/core.c | 2 +-
kernel/smpboot.c | 1 -
25 files changed, 8 insertions(+), 34 deletions(-)
diff --git a/arch/alpha/kernel/smp.c b/arch/alpha/kernel/smp.c
index f4dd9f3f3001..4b2575f936d4 100644
--- a/arch/alpha/kernel/smp.c
+++ b/arch/alpha/kernel/smp.c
@@ -166,7 +166,6 @@ smp_callin(void)
DBGS(("smp_callin: commencing CPU %d current %p active_mm %p\n",
cpuid, current, current->active_mm));
- preempt_disable();
cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
}
diff --git a/arch/arc/kernel/smp.c b/arch/arc/kernel/smp.c
index 52906d314537..db0e104d6835 100644
--- a/arch/arc/kernel/smp.c
+++ b/arch/arc/kernel/smp.c
@@ -189,7 +189,6 @@ void start_kernel_secondary(void)
pr_info("## CPU%u LIVE ##: Executing Code...\n", cpu);
local_irq_enable();
- preempt_disable();
cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
}
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 74679240a9d8..c7bb168b0d97 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -432,7 +432,6 @@ asmlinkage void secondary_start_kernel(void)
#endif
pr_debug("CPU%u: Booted secondary processor\n", cpu);
- preempt_disable();
trace_hardirqs_off();
/*
diff --git a/arch/arm64/include/asm/preempt.h b/arch/arm64/include/asm/preempt.h
index 80e946b2abee..e83f0982b99c 100644
--- a/arch/arm64/include/asm/preempt.h
+++ b/arch/arm64/include/asm/preempt.h
@@ -23,7 +23,7 @@ static inline void preempt_count_set(u64 pc)
} while (0)
#define init_idle_preempt_count(p, cpu) do { \
- task_thread_info(p)->preempt_count = PREEMPT_ENABLED; \
+ task_thread_info(p)->preempt_count = PREEMPT_DISABLED; \
} while (0)
static inline void set_preempt_need_resched(void)
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index 357590beaabb..48fd89256739 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -223,7 +223,6 @@ asmlinkage notrace void secondary_start_kernel(void)
init_gic_priority_masking();
rcu_cpu_starting(cpu);
- preempt_disable();
trace_hardirqs_off();
/*
diff --git a/arch/csky/kernel/smp.c b/arch/csky/kernel/smp.c
index 0f9f5eef9338..e2993539af8e 100644
--- a/arch/csky/kernel/smp.c
+++ b/arch/csky/kernel/smp.c
@@ -281,7 +281,6 @@ void csky_start_secondary(void)
pr_info("CPU%u Online: %s...\n", cpu, __func__);
local_irq_enable();
- preempt_disable();
cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
}
diff --git a/arch/ia64/kernel/smpboot.c b/arch/ia64/kernel/smpboot.c
index 49b488580939..d10f780c13b9 100644
--- a/arch/ia64/kernel/smpboot.c
+++ b/arch/ia64/kernel/smpboot.c
@@ -441,7 +441,6 @@ start_secondary (void *unused)
#endif
efi_map_pal_code();
cpu_init();
- preempt_disable();
smp_callin();
cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
diff --git a/arch/mips/kernel/smp.c b/arch/mips/kernel/smp.c
index ef86fbad8546..d542fb7af3ba 100644
--- a/arch/mips/kernel/smp.c
+++ b/arch/mips/kernel/smp.c
@@ -348,7 +348,6 @@ asmlinkage void start_secondary(void)
*/
calibrate_delay();
- preempt_disable();
cpu = smp_processor_id();
cpu_data[cpu].udelay_val = loops_per_jiffy;
diff --git a/arch/openrisc/kernel/smp.c b/arch/openrisc/kernel/smp.c
index 48e1092a64de..415e209732a3 100644
--- a/arch/openrisc/kernel/smp.c
+++ b/arch/openrisc/kernel/smp.c
@@ -145,8 +145,6 @@ asmlinkage __init void secondary_start_kernel(void)
set_cpu_online(cpu, true);
local_irq_enable();
-
- preempt_disable();
/*
* OK, it's off to the idle thread for us
*/
diff --git a/arch/parisc/kernel/smp.c b/arch/parisc/kernel/smp.c
index 10227f667c8a..1405b603b91b 100644
--- a/arch/parisc/kernel/smp.c
+++ b/arch/parisc/kernel/smp.c
@@ -302,7 +302,6 @@ void __init smp_callin(unsigned long pdce_proc)
#endif
smp_cpu_init(slave_id);
- preempt_disable();
flush_cache_all_local(); /* start with known state */
flush_tlb_all_local(NULL);
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 5a4d59a1070d..055ca3816eb7 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -1505,7 +1505,6 @@ void start_secondary(void *unused)
smp_store_cpu_info(cpu);
set_dec(tb_ticks_per_jiffy);
rcu_cpu_starting(cpu);
- preempt_disable();
cpu_callin_map[cpu] = 1;
if (smp_ops->setup_cpu)
diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
index 5e276c25646f..1941a6ce86a1 100644
--- a/arch/riscv/kernel/smpboot.c
+++ b/arch/riscv/kernel/smpboot.c
@@ -176,7 +176,6 @@ asmlinkage __visible void smp_callin(void)
* Disable preemption before enabling interrupts, so we don't try to
* schedule a CPU that hasn't actually started yet.
*/
- preempt_disable();
local_irq_enable();
cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
}
diff --git a/arch/s390/include/asm/preempt.h b/arch/s390/include/asm/preempt.h
index b49e0492842c..23ff51be7e29 100644
--- a/arch/s390/include/asm/preempt.h
+++ b/arch/s390/include/asm/preempt.h
@@ -32,7 +32,7 @@ static inline void preempt_count_set(int pc)
#define init_task_preempt_count(p) do { } while (0)
#define init_idle_preempt_count(p, cpu) do { \
- S390_lowcore.preempt_count = PREEMPT_ENABLED; \
+ S390_lowcore.preempt_count = PREEMPT_DISABLED; \
} while (0)
static inline void set_preempt_need_resched(void)
@@ -91,7 +91,7 @@ static inline void preempt_count_set(int pc)
#define init_task_preempt_count(p) do { } while (0)
#define init_idle_preempt_count(p, cpu) do { \
- S390_lowcore.preempt_count = PREEMPT_ENABLED; \
+ S390_lowcore.preempt_count = PREEMPT_DISABLED; \
} while (0)
static inline void set_preempt_need_resched(void)
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index 58c8afa3da65..d60c7374d807 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -877,7 +877,6 @@ static void smp_init_secondary(void)
restore_access_regs(S390_lowcore.access_regs_save_area);
cpu_init();
rcu_cpu_starting(cpu);
- preempt_disable();
init_cpu_timer();
vtime_init();
vdso_getcpu_init();
diff --git a/arch/sh/kernel/smp.c b/arch/sh/kernel/smp.c
index 372acdc9033e..65924d9ec245 100644
--- a/arch/sh/kernel/smp.c
+++ b/arch/sh/kernel/smp.c
@@ -186,8 +186,6 @@ asmlinkage void start_secondary(void)
per_cpu_trap_init();
- preempt_disable();
-
notify_cpu_starting(cpu);
local_irq_enable();
diff --git a/arch/sparc/kernel/smp_32.c b/arch/sparc/kernel/smp_32.c
index 50c127ab46d5..22b148e5a5f8 100644
--- a/arch/sparc/kernel/smp_32.c
+++ b/arch/sparc/kernel/smp_32.c
@@ -348,7 +348,6 @@ static void sparc_start_secondary(void *arg)
*/
arch_cpu_pre_starting(arg);
- preempt_disable();
cpu = smp_processor_id();
notify_cpu_starting(cpu);
diff --git a/arch/sparc/kernel/smp_64.c b/arch/sparc/kernel/smp_64.c
index e38d8bf454e8..ae5faa1d989d 100644
--- a/arch/sparc/kernel/smp_64.c
+++ b/arch/sparc/kernel/smp_64.c
@@ -138,9 +138,6 @@ void smp_callin(void)
set_cpu_online(cpuid, true);
- /* idle thread is expected to have preempt disabled */
- preempt_disable();
-
local_irq_enable();
cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
diff --git a/arch/x86/include/asm/preempt.h b/arch/x86/include/asm/preempt.h
index f8cb8af4de5c..fe5efbcba824 100644
--- a/arch/x86/include/asm/preempt.h
+++ b/arch/x86/include/asm/preempt.h
@@ -44,7 +44,7 @@ static __always_inline void preempt_count_set(int pc)
#define init_task_preempt_count(p) do { } while (0)
#define init_idle_preempt_count(p, cpu) do { \
- per_cpu(__preempt_count, (cpu)) = PREEMPT_ENABLED; \
+ per_cpu(__preempt_count, (cpu)) = PREEMPT_DISABLED; \
} while (0)
/*
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 16703c35a944..29713d0cf155 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -236,7 +236,6 @@ static void notrace start_secondary(void *unused)
cpu_init();
rcu_cpu_starting(raw_smp_processor_id());
x86_cpuinit.early_percpu_clock_init();
- preempt_disable();
smp_callin();
enable_start_cpu0 = 0;
diff --git a/arch/xtensa/kernel/smp.c b/arch/xtensa/kernel/smp.c
index cd85a7a2722b..1254da07ead1 100644
--- a/arch/xtensa/kernel/smp.c
+++ b/arch/xtensa/kernel/smp.c
@@ -145,7 +145,6 @@ void secondary_start_kernel(void)
cpumask_set_cpu(cpu, mm_cpumask(mm));
enter_lazy_tlb(mm, current);
- preempt_disable();
trace_hardirqs_off();
calibrate_delay();
diff --git a/include/asm-generic/preempt.h b/include/asm-generic/preempt.h
index d683f5e6d791..b4d43a4af5f7 100644
--- a/include/asm-generic/preempt.h
+++ b/include/asm-generic/preempt.h
@@ -29,7 +29,7 @@ static __always_inline void preempt_count_set(int pc)
} while (0)
#define init_idle_preempt_count(p, cpu) do { \
- task_thread_info(p)->preempt_count = PREEMPT_ENABLED; \
+ task_thread_info(p)->preempt_count = PREEMPT_DISABLED; \
} while (0)
static __always_inline void set_preempt_need_resched(void)
diff --git a/init/main.c b/init/main.c
index 53b278845b88..d8580323110e 100644
--- a/init/main.c
+++ b/init/main.c
@@ -918,11 +918,7 @@ asmlinkage __visible void __init __no_sanitize_address start_kernel(void)
* time - but meanwhile we still have a functioning scheduler.
*/
sched_init();
- /*
- * Disable preemption - early bootup scheduling is extremely
- * fragile until we cpu_idle() for the first time.
- */
- preempt_disable();
+
if (WARN(!irqs_disabled(),
"Interrupts were enabled *very* early, fixing it\n"))
local_irq_disable();
diff --git a/kernel/fork.c b/kernel/fork.c
index a1a763019bfb..9de7bc40be1d 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -2406,7 +2406,7 @@ static inline void init_idle_pids(struct task_struct *idle)
}
}
-struct task_struct *fork_idle(int cpu)
+struct task_struct * __init fork_idle(int cpu)
{
struct task_struct *task;
struct kernel_clone_args args = {
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 4a0668acd876..43b903ae823b 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -7433,7 +7433,7 @@ void show_state_filter(unsigned long state_filter)
* NOTE: this function does not set the idle thread's NEED_RESCHED
* flag, to make booting more robust.
*/
-void init_idle(struct task_struct *idle, int cpu)
+void __init init_idle(struct task_struct *idle, int cpu)
{
struct rq *rq = cpu_rq(cpu);
unsigned long flags;
diff --git a/kernel/smpboot.c b/kernel/smpboot.c
index f25208e8df83..e4163042c4d6 100644
--- a/kernel/smpboot.c
+++ b/kernel/smpboot.c
@@ -33,7 +33,6 @@ struct task_struct *idle_thread_get(unsigned int cpu)
if (!tsk)
return ERR_PTR(-ENOMEM);
- init_idle(tsk, cpu);
return tsk;
}
--
2.25.1
^ permalink raw reply related
* Re: [PATCH kernel v2] powerpc/makefile: Do not redefine $(CPP) for preprocessor
From: Segher Boessenkool @ 2021-05-12 10:26 UTC (permalink / raw)
To: Alexey Kardashevskiy
Cc: Michal Marek, linux-kbuild, Masahiro Yamada, Nick Desaulniers,
linux-kernel, Nicholas Piggin, Nathan Chancellor,
clang-built-linux, linuxppc-dev
In-Reply-To: <80ae1561-ed8d-cf3a-f3bb-d89cd07bfc24@ozlabs.ru>
On Wed, May 12, 2021 at 01:48:53PM +1000, Alexey Kardashevskiy wrote:
> >Oh! I completely missed those few lines. Sorry for that :-(
>
> Well, I probably should have made it a separate patch anyway, I'll
> repost separately.
Thanks.
> >To compensate a bit:
> >
> >>It still puzzles me why we need -C
> >>(preserve comments in the preprocessor output) flag here.
> >
> >It is so that a human can look at the output and read it. Comments are
> >very significant to human readers :-)
>
> I seriously doubt anyone ever read those :)
I am pretty sure whoever wrote it did!
> I suspect this is to pull
> all the licenses in one place and do some checking but I did not dig deep.
I don't see the point in that, but :-)
Segher
^ permalink raw reply
* [PATCH 1/5] kbuild: require all architectures to have arch/$(SRCARCH)/Kbuild
From: Masahiro Yamada @ 2021-05-12 7:57 UTC (permalink / raw)
To: linux-kbuild
Cc: Rich Felker, linux-ia64, linux-sh, linux-mips,
James E.J. Bottomley, Max Filippov, Guo Ren, linux-csky,
H. Peter Anvin, sparclinux, linux-hexagon, linux-riscv,
Vincent Chen, Will Deacon, Thomas Gleixner, Paul Mackerras,
Anton Ivanov, Jonas Bonn, linux-s390, Brian Cain, Masahiro Yamada,
x86, Russell King, Ley Foon Tan, Christian Borntraeger,
Ingo Molnar, linux-parisc, Catalin Marinas, Matt Turner,
linux-snps-arc, Heiko Carstens, uclinux-h8-devel, linux-xtensa,
Albert Ou, Vasily Gorbik, Jeff Dike, linux-alpha, linux-um,
Stefan Kristiansson, Thomas Bogendoerfer, Ivan Kokshaysky,
Greentime Hu, Paul Walmsley, Stafford Horne, linux-arm-kernel,
Richard Henderson, Chris Zankel, Michal Simek, Michal Marek,
Yoshinori Sato, Nick Hu, Vineet Gupta, linux-kernel,
David S. Miller, openrisc, Palmer Dabbelt, Richard Weinberger,
Borislav Petkov, linuxppc-dev, Helge Deller
arch/$(SRCARCH)/Kbuild is useful for Makefile cleanups because you can
use the obj-y syntax.
Add an empty file if it is missing in arch/$(SRCARCH)/.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---
Makefile | 2 +-
arch/alpha/Kbuild | 1 +
arch/arc/Makefile | 3 ---
arch/arm/Makefile | 1 -
arch/arm64/Makefile | 1 -
arch/csky/Kbuild | 1 +
arch/h8300/Kbuild | 1 +
arch/hexagon/Kbuild | 1 +
arch/ia64/Kbuild | 1 +
arch/microblaze/Kbuild | 1 +
arch/mips/Makefile | 3 ---
arch/nds32/Kbuild | 1 +
arch/nios2/Kbuild | 1 +
arch/openrisc/Makefile | 1 -
arch/parisc/Kbuild | 1 +
arch/powerpc/Makefile | 3 ---
arch/riscv/Makefile | 1 -
arch/s390/Makefile | 3 ---
arch/sh/Kbuild | 1 +
arch/sparc/Makefile | 3 ---
arch/um/Kbuild | 1 +
arch/x86/Makefile | 3 ---
arch/xtensa/Kbuild | 1 +
23 files changed, 13 insertions(+), 23 deletions(-)
create mode 100644 arch/alpha/Kbuild
create mode 100644 arch/csky/Kbuild
create mode 100644 arch/h8300/Kbuild
create mode 100644 arch/hexagon/Kbuild
create mode 100644 arch/ia64/Kbuild
create mode 100644 arch/microblaze/Kbuild
create mode 100644 arch/nds32/Kbuild
create mode 100644 arch/nios2/Kbuild
create mode 100644 arch/parisc/Kbuild
create mode 100644 arch/sh/Kbuild
create mode 100644 arch/um/Kbuild
create mode 100644 arch/xtensa/Kbuild
diff --git a/Makefile b/Makefile
index 15b6476d0f89..7df040b1b023 100644
--- a/Makefile
+++ b/Makefile
@@ -658,7 +658,7 @@ endif
ifeq ($(KBUILD_EXTMOD),)
# Objects we will link into vmlinux / subdirs we need to visit
-core-y := init/ usr/
+core-y := init/ usr/ arch/$(SRCARCH)/
drivers-y := drivers/ sound/
drivers-$(CONFIG_SAMPLES) += samples/
drivers-$(CONFIG_NET) += net/
diff --git a/arch/alpha/Kbuild b/arch/alpha/Kbuild
new file mode 100644
index 000000000000..a4e40e534e6a
--- /dev/null
+++ b/arch/alpha/Kbuild
@@ -0,0 +1 @@
+# SPDX-License-Identifier: GPL-2.0-only
diff --git a/arch/arc/Makefile b/arch/arc/Makefile
index 4392c9c189c4..3e6d4b84797f 100644
--- a/arch/arc/Makefile
+++ b/arch/arc/Makefile
@@ -85,9 +85,6 @@ KBUILD_LDFLAGS += $(ldflags-y)
head-y := arch/arc/kernel/head.o
-# See arch/arc/Kbuild for content of core part of the kernel
-core-y += arch/arc/
-
# w/o this dtb won't embed into kernel binary
core-y += arch/arc/boot/dts/
diff --git a/arch/arm/Makefile b/arch/arm/Makefile
index 415c3514573a..173da685a52e 100644
--- a/arch/arm/Makefile
+++ b/arch/arm/Makefile
@@ -252,7 +252,6 @@ endif
export TEXT_OFFSET GZFLAGS MMUEXT
-core-y += arch/arm/
# If we have a machine-specific directory, then include it in the build.
core-y += $(machdirs) $(platdirs)
diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
index 7ef44478560d..b73c151f3a53 100644
--- a/arch/arm64/Makefile
+++ b/arch/arm64/Makefile
@@ -149,7 +149,6 @@ KBUILD_CFLAGS += -DKASAN_SHADOW_SCALE_SHIFT=$(KASAN_SHADOW_SCALE_SHIFT)
KBUILD_CPPFLAGS += -DKASAN_SHADOW_SCALE_SHIFT=$(KASAN_SHADOW_SCALE_SHIFT)
KBUILD_AFLAGS += -DKASAN_SHADOW_SCALE_SHIFT=$(KASAN_SHADOW_SCALE_SHIFT)
-core-y += arch/arm64/
libs-y := arch/arm64/lib/ $(libs-y)
libs-$(CONFIG_EFI_STUB) += $(objtree)/drivers/firmware/efi/libstub/lib.a
diff --git a/arch/csky/Kbuild b/arch/csky/Kbuild
new file mode 100644
index 000000000000..a4e40e534e6a
--- /dev/null
+++ b/arch/csky/Kbuild
@@ -0,0 +1 @@
+# SPDX-License-Identifier: GPL-2.0-only
diff --git a/arch/h8300/Kbuild b/arch/h8300/Kbuild
new file mode 100644
index 000000000000..a4e40e534e6a
--- /dev/null
+++ b/arch/h8300/Kbuild
@@ -0,0 +1 @@
+# SPDX-License-Identifier: GPL-2.0-only
diff --git a/arch/hexagon/Kbuild b/arch/hexagon/Kbuild
new file mode 100644
index 000000000000..a4e40e534e6a
--- /dev/null
+++ b/arch/hexagon/Kbuild
@@ -0,0 +1 @@
+# SPDX-License-Identifier: GPL-2.0-only
diff --git a/arch/ia64/Kbuild b/arch/ia64/Kbuild
new file mode 100644
index 000000000000..a4e40e534e6a
--- /dev/null
+++ b/arch/ia64/Kbuild
@@ -0,0 +1 @@
+# SPDX-License-Identifier: GPL-2.0-only
diff --git a/arch/microblaze/Kbuild b/arch/microblaze/Kbuild
new file mode 100644
index 000000000000..a4e40e534e6a
--- /dev/null
+++ b/arch/microblaze/Kbuild
@@ -0,0 +1 @@
+# SPDX-License-Identifier: GPL-2.0-only
diff --git a/arch/mips/Makefile b/arch/mips/Makefile
index 258234c35a09..4e942b7ef022 100644
--- a/arch/mips/Makefile
+++ b/arch/mips/Makefile
@@ -332,9 +332,6 @@ head-y := arch/mips/kernel/head.o
libs-y += arch/mips/lib/
libs-$(CONFIG_MIPS_FP_SUPPORT) += arch/mips/math-emu/
-# See arch/mips/Kbuild for content of core part of the kernel
-core-y += arch/mips/
-
drivers-y += arch/mips/crypto/
# suspend and hibernation support
diff --git a/arch/nds32/Kbuild b/arch/nds32/Kbuild
new file mode 100644
index 000000000000..a4e40e534e6a
--- /dev/null
+++ b/arch/nds32/Kbuild
@@ -0,0 +1 @@
+# SPDX-License-Identifier: GPL-2.0-only
diff --git a/arch/nios2/Kbuild b/arch/nios2/Kbuild
new file mode 100644
index 000000000000..a4e40e534e6a
--- /dev/null
+++ b/arch/nios2/Kbuild
@@ -0,0 +1 @@
+# SPDX-License-Identifier: GPL-2.0-only
diff --git a/arch/openrisc/Makefile b/arch/openrisc/Makefile
index 410e7abfac69..c52de526e518 100644
--- a/arch/openrisc/Makefile
+++ b/arch/openrisc/Makefile
@@ -42,7 +42,6 @@ endif
head-y := arch/openrisc/kernel/head.o
-core-y += arch/openrisc/
libs-y += $(LIBGCC)
PHONY += vmlinux.bin
diff --git a/arch/parisc/Kbuild b/arch/parisc/Kbuild
new file mode 100644
index 000000000000..a4e40e534e6a
--- /dev/null
+++ b/arch/parisc/Kbuild
@@ -0,0 +1 @@
+# SPDX-License-Identifier: GPL-2.0-only
diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
index 3212d076ac6a..af669aa75b73 100644
--- a/arch/powerpc/Makefile
+++ b/arch/powerpc/Makefile
@@ -267,9 +267,6 @@ head-$(CONFIG_PPC_FPU) += arch/powerpc/kernel/fpu.o
head-$(CONFIG_ALTIVEC) += arch/powerpc/kernel/vector.o
head-$(CONFIG_PPC_OF_BOOT_TRAMPOLINE) += arch/powerpc/kernel/prom_init.o
-# See arch/powerpc/Kbuild for content of core part of the kernel
-core-y += arch/powerpc/
-
# Default to zImage, override when needed
all: zImage
diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile
index 3eb9590a0775..c5f359540862 100644
--- a/arch/riscv/Makefile
+++ b/arch/riscv/Makefile
@@ -90,7 +90,6 @@ endif
head-y := arch/riscv/kernel/head.o
-core-y += arch/riscv/
core-$(CONFIG_RISCV_ERRATA_ALTERNATIVE) += arch/riscv/errata/
libs-y += arch/riscv/lib/
diff --git a/arch/s390/Makefile b/arch/s390/Makefile
index e443ed9947bd..37b61645694c 100644
--- a/arch/s390/Makefile
+++ b/arch/s390/Makefile
@@ -128,9 +128,6 @@ OBJCOPYFLAGS := -O binary
head-y := arch/s390/kernel/head64.o
-# See arch/s390/Kbuild for content of core part of the kernel
-core-y += arch/s390/
-
libs-y += arch/s390/lib/
drivers-y += drivers/s390/
diff --git a/arch/sh/Kbuild b/arch/sh/Kbuild
new file mode 100644
index 000000000000..a4e40e534e6a
--- /dev/null
+++ b/arch/sh/Kbuild
@@ -0,0 +1 @@
+# SPDX-License-Identifier: GPL-2.0-only
diff --git a/arch/sparc/Makefile b/arch/sparc/Makefile
index bee99e65fe23..4e65245bc755 100644
--- a/arch/sparc/Makefile
+++ b/arch/sparc/Makefile
@@ -58,9 +58,6 @@ endif
head-y := arch/sparc/kernel/head_$(BITS).o
-# See arch/sparc/Kbuild for the core part of the kernel
-core-y += arch/sparc/
-
libs-y += arch/sparc/prom/
libs-y += arch/sparc/lib/
diff --git a/arch/um/Kbuild b/arch/um/Kbuild
new file mode 100644
index 000000000000..a4e40e534e6a
--- /dev/null
+++ b/arch/um/Kbuild
@@ -0,0 +1 @@
+# SPDX-License-Identifier: GPL-2.0-only
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index c77c5d8a7b3e..4307bf48ec53 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -239,9 +239,6 @@ head-y += arch/x86/kernel/platform-quirks.o
libs-y += arch/x86/lib/
-# See arch/x86/Kbuild for content of core part of the kernel
-core-y += arch/x86/
-
# drivers-y are linked after core-y
drivers-$(CONFIG_MATH_EMULATION) += arch/x86/math-emu/
drivers-$(CONFIG_PCI) += arch/x86/pci/
diff --git a/arch/xtensa/Kbuild b/arch/xtensa/Kbuild
new file mode 100644
index 000000000000..a4e40e534e6a
--- /dev/null
+++ b/arch/xtensa/Kbuild
@@ -0,0 +1 @@
+# SPDX-License-Identifier: GPL-2.0-only
--
2.27.0
^ permalink raw reply related
* Re: [PATCH] powerpc: Force inlining of csum_add()
From: Christophe Leroy @ 2021-05-12 12:56 UTC (permalink / raw)
To: Segher Boessenkool; +Cc: Paul Mackerras, linuxppc-dev, linux-kernel
In-Reply-To: <20210511105154.GJ10366@gate.crashing.org>
Hi,
Le 11/05/2021 à 12:51, Segher Boessenkool a écrit :
> Hi!
>
> On Tue, May 11, 2021 at 06:08:06AM +0000, Christophe Leroy wrote:
>> Commit 328e7e487a46 ("powerpc: force inlining of csum_partial() to
>> avoid multiple csum_partial() with GCC10") inlined csum_partial().
>>
>> Now that csum_partial() is inlined, GCC outlines csum_add() when
>> called by csum_partial().
>
>> c064fb28 <csum_add>:
>> c064fb28: 7c 63 20 14 addc r3,r3,r4
>> c064fb2c: 7c 63 01 94 addze r3,r3
>> c064fb30: 4e 80 00 20 blr
>
> Could you build this with -fdump-tree-einline-all and send me the
> results? Or open a GCC PR yourself :-)
Ok, I'll forward it to you in a minute.
>
> Something seems to have decided this asm is more expensive than it is.
> That isn't always avoidable -- the compiler cannot look inside asms --
> but it seems it could be improved here.
>
> Do you have (or can make) a self-contained testcase?
I have not tried, and I fear it might be difficult, because on a kernel build with dozens of calls
to csum_add(), only ip6_tunnel.o exhibits such an issue.
>
>> The sum with 0 is useless, should have been skipped.
>
> That isn't something the compiler can do anything about (not sure if you
> were suggesting that); it has to be done in the user code (and it tries
> to already, see below).
I was not suggesting that, only that when properly inlined the sum with 0 is skipped (because we put
the necessary stuff in csum_add() of course).
>
>> And there is even one completely unused instance of csum_add().
>
> That is strange, that should never happen.
It seems that several .o include unused versions of csum_add. After the final link, one remains (in
addition to the used one) in vmlinux.
>
>> ./arch/powerpc/include/asm/checksum.h: In function '__ip6_tnl_rcv':
>> ./arch/powerpc/include/asm/checksum.h:94:22: warning: inlining failed in call to 'csum_add': call is unlikely and code size would grow [-Winline]
>> 94 | static inline __wsum csum_add(__wsum csum, __wsum addend)
>> | ^~~~~~~~
>> ./arch/powerpc/include/asm/checksum.h:172:31: note: called from here
>> 172 | sum = csum_add(sum, (__force __wsum)*(const u32 *)buff);
>> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> At least we say what happened. Progress! :-)
Lol. I've seen this warning for long, that's not something new I guess.
>
>> In the non-inlined version, the first sum with 0 was performed.
>> Here it is skipped.
>
> That is because of how __builtin_constant_p works, most likely. As we
> discussed elsewhere it is evaluated before all forms of loop unrolling.
But we are not talking about loop unrolling here, are we ?
It seems that the reason here is that __builtin_constant_p() is evaluated long after GCC decided to
not inline that call to csum_add().
Christophe
^ permalink raw reply
* Re: [PATCH] lockdown, selinux: fix bogus SELinux lockdown permission checks
From: Ondrej Mosnacek @ 2021-05-12 13:21 UTC (permalink / raw)
To: Casey Schaufler
Cc: SElinux list, network dev, Stephen Smalley, James Morris,
Steven Rostedt, Linux kernel mailing list,
Linux Security Module list, Ingo Molnar, Linux FS Devel, bpf,
linuxppc-dev
In-Reply-To: <a8d138a6-1d34-1457-9266-4abeddb6fdba@schaufler-ca.com>
On Sat, May 8, 2021 at 12:17 AM Casey Schaufler <casey@schaufler-ca.com> wrote:
> On 5/7/2021 4:40 AM, Ondrej Mosnacek wrote:
> > Commit 59438b46471a ("security,lockdown,selinux: implement SELinux
> > lockdown") added an implementation of the locked_down LSM hook to
> > SELinux, with the aim to restrict which domains are allowed to perform
> > operations that would breach lockdown.
> >
> > However, in several places the security_locked_down() hook is called in
> > situations where the current task isn't doing any action that would
> > directly breach lockdown, leading to SELinux checks that are basically
> > bogus.
> >
> > Since in most of these situations converting the callers such that
> > security_locked_down() is called in a context where the current task
> > would be meaningful for SELinux is impossible or very non-trivial (and
> > could lead to TOCTOU issues for the classic Lockdown LSM
> > implementation), fix this by adding a separate hook
> > security_locked_down_globally()
>
> This is a poor solution to the stated problem. Rather than adding
> a new hook you should add the task as a parameter to the existing hook
> and let the security modules do as they will based on its value.
> If the caller does not have an appropriate task it should pass NULL.
> The lockdown LSM can ignore the task value and SELinux can make its
> own decision based on the task value passed.
The problem with that approach is that all callers would then need to
be updated and I intended to keep the patch small as I'd like it to go
to stable kernels as well.
But it does seem to be a better long-term solution - would it work for
you (and whichever maintainer would be taking the patch(es)) if I just
added another patch that refactors it to use the task parameter?
--
Ondrej Mosnacek
Software Engineer, Linux Security - SELinux kernel
Red Hat, Inc.
^ permalink raw reply
* [PATCH 1/2] kprobes: Allow architectures to override optinsn page allocation
From: Christophe Leroy @ 2021-05-12 14:29 UTC (permalink / raw)
To: Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman,
naveen.n.rao, anil.s.keshavamurthy, davem, mhiramat
Cc: clang-built-linux, linuxppc-dev, linux-kernel
Some architectures like powerpc require a non standard
allocation of optinsn page, because module pages are
too far from the kernel for direct branches.
Define weak alloc_optinsn_page() and free_optinsn_page(), that
fall back on alloc_insn_page() and free_insn_page() when not
overriden by the architecture.
Suggested-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
kernel/kprobes.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 745f08fdd7a6..8c0a6fdef771 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -321,11 +321,21 @@ int kprobe_cache_get_kallsym(struct kprobe_insn_cache *c, unsigned int *symnum,
}
#ifdef CONFIG_OPTPROBES
+void __weak *alloc_optinsn_page(void)
+{
+ return alloc_insn_page();
+}
+
+void __weak free_optinsn_page(void *page)
+{
+ free_insn_page(page);
+}
+
/* For optimized_kprobe buffer */
struct kprobe_insn_cache kprobe_optinsn_slots = {
.mutex = __MUTEX_INITIALIZER(kprobe_optinsn_slots.mutex),
- .alloc = alloc_insn_page,
- .free = free_insn_page,
+ .alloc = alloc_optinsn_page,
+ .free = free_optinsn_page,
.sym = KPROBE_OPTINSN_PAGE_SYM,
.pages = LIST_HEAD_INIT(kprobe_optinsn_slots.pages),
/* .insn_size is initialized later */
--
2.25.0
^ permalink raw reply related
* [PATCH 2/2] powerpc/kprobes: Replace ppc_optinsn by common optinsn
From: Christophe Leroy @ 2021-05-12 14:29 UTC (permalink / raw)
To: Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman,
naveen.n.rao, anil.s.keshavamurthy, davem, mhiramat
Cc: clang-built-linux, linuxppc-dev, linux-kernel
In-Reply-To: <472c597cc8cc8f74f037acf971f7799fb381a647.1620829724.git.christophe.leroy@csgroup.eu>
Commit 51c9c0843993 ("powerpc/kprobes: Implement Optprobes")
implemented a powerpc specific version of optinsn in order
to workaround the 32Mb limitation for direct branches.
Instead of implementing a dedicated powerpc version, use the
common optinsn and override the allocation and freeing functions.
This also indirectly remove the CLANG warning about
is_kprobe_ppc_optinsn_slot() not being use, and the powerpc will
now benefit from commit 5b485629ba0d ("kprobes, extable: Identify
kprobes trampolines as kernel text area")
Suggested-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
arch/powerpc/kernel/optprobes.c | 23 +++++------------------
1 file changed, 5 insertions(+), 18 deletions(-)
diff --git a/arch/powerpc/kernel/optprobes.c b/arch/powerpc/kernel/optprobes.c
index cdf87086fa33..a370190cd02a 100644
--- a/arch/powerpc/kernel/optprobes.c
+++ b/arch/powerpc/kernel/optprobes.c
@@ -31,11 +31,9 @@
#define TMPL_END_IDX \
(optprobe_template_end - optprobe_template_entry)
-DEFINE_INSN_CACHE_OPS(ppc_optinsn);
-
static bool insn_page_in_use;
-static void *__ppc_alloc_insn_page(void)
+void *alloc_optinsn_page(void)
{
if (insn_page_in_use)
return NULL;
@@ -43,20 +41,11 @@ static void *__ppc_alloc_insn_page(void)
return &optinsn_slot;
}
-static void __ppc_free_insn_page(void *page __maybe_unused)
+void free_optinsn_page(void *page)
{
insn_page_in_use = false;
}
-struct kprobe_insn_cache kprobe_ppc_optinsn_slots = {
- .mutex = __MUTEX_INITIALIZER(kprobe_ppc_optinsn_slots.mutex),
- .pages = LIST_HEAD_INIT(kprobe_ppc_optinsn_slots.pages),
- /* insn_size initialized later */
- .alloc = __ppc_alloc_insn_page,
- .free = __ppc_free_insn_page,
- .nr_garbage = 0,
-};
-
/*
* Check if we can optimize this probe. Returns NIP post-emulation if this can
* be optimized and 0 otherwise.
@@ -136,7 +125,7 @@ NOKPROBE_SYMBOL(optimized_callback);
void arch_remove_optimized_kprobe(struct optimized_kprobe *op)
{
if (op->optinsn.insn) {
- free_ppc_optinsn_slot(op->optinsn.insn, 1);
+ free_optinsn_slot(op->optinsn.insn, 1);
op->optinsn.insn = NULL;
}
}
@@ -203,14 +192,12 @@ int arch_prepare_optimized_kprobe(struct optimized_kprobe *op, struct kprobe *p)
unsigned long nip, size;
int rc, i;
- kprobe_ppc_optinsn_slots.insn_size = MAX_OPTINSN_SIZE;
-
nip = can_optimize(p);
if (!nip)
return -EILSEQ;
/* Allocate instruction slot for detour buffer */
- buff = get_ppc_optinsn_slot();
+ buff = get_optinsn_slot();
if (!buff)
return -ENOMEM;
@@ -297,7 +284,7 @@ int arch_prepare_optimized_kprobe(struct optimized_kprobe *op, struct kprobe *p)
return 0;
error:
- free_ppc_optinsn_slot(buff, 0);
+ free_optinsn_slot(buff, 0);
return -ERANGE;
}
--
2.25.0
^ permalink raw reply related
* Re: [PATCH] powerpc: Force inlining of csum_add()
From: Segher Boessenkool @ 2021-05-12 14:31 UTC (permalink / raw)
To: Christophe Leroy; +Cc: Paul Mackerras, linuxppc-dev, linux-kernel
In-Reply-To: <e996ef13-c25c-5e9c-edd2-444eded88802@csgroup.eu>
On Wed, May 12, 2021 at 02:56:56PM +0200, Christophe Leroy wrote:
> Le 11/05/2021 à 12:51, Segher Boessenkool a écrit :
> >Something seems to have decided this asm is more expensive than it is.
> >That isn't always avoidable -- the compiler cannot look inside asms --
> >but it seems it could be improved here.
> >
> >Do you have (or can make) a self-contained testcase?
>
> I have not tried, and I fear it might be difficult, because on a kernel
> build with dozens of calls to csum_add(), only ip6_tunnel.o exhibits such
> an issue.
Yeah. Sometimes you can force some of the decisions, but that usually
requires knowing too many GCC internals :-/
> >>And there is even one completely unused instance of csum_add().
> >
> >That is strange, that should never happen.
>
> It seems that several .o include unused versions of csum_add. After the
> final link, one remains (in addition to the used one) in vmlinux.
But it is a static function, so it should not end up in any object file
where it isn't used.
> >>In the non-inlined version, the first sum with 0 was performed.
> >>Here it is skipped.
> >
> >That is because of how __builtin_constant_p works, most likely. As we
> >discussed elsewhere it is evaluated before all forms of loop unrolling.
>
> But we are not talking about loop unrolling here, are we ?
Oh, right you are, but that doesn't change much. The
_builtin_constant_p(len) is evaluated long before the compiler sees len
is a constant here.
> It seems that the reason here is that __builtin_constant_p() is evaluated
> long after GCC decided to not inline that call to csum_add().
Yes, it seems we do not currently do even trivial inlining except very
early in the compiler.
Thanks,
Segher
^ permalink raw reply
* Re: [PATCH] powerpc: Force inlining of csum_add()
From: Christophe Leroy @ 2021-05-12 14:43 UTC (permalink / raw)
To: Segher Boessenkool; +Cc: Paul Mackerras, linuxppc-dev, linux-kernel
In-Reply-To: <20210512143105.GW10366@gate.crashing.org>
Le 12/05/2021 à 16:31, Segher Boessenkool a écrit :
> On Wed, May 12, 2021 at 02:56:56PM +0200, Christophe Leroy wrote:
>> Le 11/05/2021 à 12:51, Segher Boessenkool a écrit :
>>> Something seems to have decided this asm is more expensive than it is.
>>> That isn't always avoidable -- the compiler cannot look inside asms --
>>> but it seems it could be improved here.
>>>
>>> Do you have (or can make) a self-contained testcase?
>>
>> I have not tried, and I fear it might be difficult, because on a kernel
>> build with dozens of calls to csum_add(), only ip6_tunnel.o exhibits such
>> an issue.
>
> Yeah. Sometimes you can force some of the decisions, but that usually
> requires knowing too many GCC internals :-/
>
>>>> And there is even one completely unused instance of csum_add().
>>>
>>> That is strange, that should never happen.
>>
>> It seems that several .o include unused versions of csum_add. After the
>> final link, one remains (in addition to the used one) in vmlinux.
>
> But it is a static function, so it should not end up in any object file
> where it isn't used.
Well .... did I dream ?
Now I only find one extra .o with unused csum_add() : That's net/ipv6/exthdrs.o
It matches the one found in vmlinux.
Are you interested in -fdump-tree-einline-all for that one as well ?
Christophe
^ permalink raw reply
* Re: [PATCH v3 0/4] P2040/P2041 i2c recovery erratum
From: wsa @ 2021-05-12 15:01 UTC (permalink / raw)
To: Joakim Tjernlund
Cc: devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
andy.shevchenko@gmail.com, robh+dt@kernel.org,
linux-i2c@vger.kernel.org, Chris.Packham@alliedtelesis.co.nz,
andriy.shevchenko@linux.intel.com, linuxppc-dev@lists.ozlabs.org
In-Reply-To: <4e96247275d559bab133d6c318276fa6be4d7be0.camel@infinera.com>
[-- Attachment #1: Type: text/plain, Size: 702 bytes --]
> > I've been doing my recent work with a P2040 and prior to that I did test
> > out the recovery on a T2081 (which isn't documented to have this
> > erratum) when I was re-working the driver. The "new" recovery actually
> > seems better but I don't have a reliably faulty i2c device so that's
> > only based on me writing some code to manually trigger the recovery
> > (using the snippet below) and observing it with an oscilloscope.
>
> You don't need a faulty device, just an aborted I2C read/write op.
If you can wire GPIOs to the bus, you can use the I2C fault injector:
Documentation/i2c/gpio-fault-injection.rst
There are already two "incomplete transfer" injectors.
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]
^ permalink raw reply
* Re: [RFC PATCH 0/7] Memory hotplug/hotremove at subsection size
From: David Hildenbrand @ 2021-05-12 16:14 UTC (permalink / raw)
To: Zi Yan, Michal Hocko
Cc: linux-ia64, Wei Yang, Anshuman Khandual, Rafael J . Wysocki, x86,
Dan Williams, linux-kernel, linux-mm, Andy Lutomirski,
Thomas Gleixner, linuxppc-dev, Andrew Morton, Mike Rapoport,
Oscar Salvador
In-Reply-To: <746780E5-0288-494D-8B19-538049F1B891@nvidia.com>
>>
>> As stated somewhere here already, we'll have to look into making alloc_contig_range() (and main users CMA and virtio-mem) independent of MAX_ORDER and mainly rely on pageblock_order. The current handling in alloc_contig_range() is far from optimal as we have to isolate a whole MAX_ORDER - 1 page -- and on ZONE_NORMAL we'll fail easily if any part contains something unmovable although we don't even want to allocate that part. I actually have that on my list (to be able to fully support pageblock_order instead of MAX_ORDER -1 chunks in virtio-mem), however didn't have time to look into it.
>
> So in your mind, for gigantic page allocation (> MAX_ORDER), alloc_contig_range()
> should be used instead of buddy allocator while pageblock_order is kept at a small
> granularity like 2MB. Is that the case? Isn’t it going to have high fail rate
> when any of the pageblocks within a gigantic page range (like 1GB) becomes unmovable?
> Are you thinking additional mechanism/policy to prevent such thing happening as
> an additional step for gigantic page allocation? Like your ZONE_PREFER_MOVABLE idea?
>
I am not fully sure yet where the journey will go , I guess nobody
knows. Ultimately, having buddy support for >= current MAX_ORDER (IOW,
increasing MAX_ORDER) will most probably happen, so it would be worth
investigating what has to be done to get that running as a first step.
Of course, we could temporarily think about wiring it up in the buddy like
if (order < MAX_ORDER)
__alloc_pages()...
else
alloc_contig_pages()
but it doesn't really improve the situation IMHO, just an API change.
So I think we should look into increasing MAX_ORDER, seeing what needs
to be done to have that part running while keeping the section size and
the pageblock order as is. I know that at least memory
onlining/offlining, cma, alloc_contig_range(), ... needs tweaking,
especially when we don't increase the section size (but also if we would
due to the way page isolation is currently handled). Having a MAX_ORDER
-1 page being partially in different nodes might be another thing to
look into (I heard that it can already happen right now, but I don't
remember the details).
The next step after that would then be better fragmentation avoidance
for larger granularity like 1G THP.
>>
>> Further, page onlining / offlining code and early init code most probably also needs care if MAX_ORDER - 1 crosses sections. Memory holes we might suddenly have in MAX_ORDER - 1 pages might become a problem and will have to be handled. Not sure which other code has to be tweaked (compaction? page isolation?).
>
> Can you elaborate it a little more? From what I understand, memory holes mean valid
> PFNs are not contiguous before and after a hole, so pfn++ will not work, but
> struct pages are still virtually contiguous assuming SPARSE_VMEMMAP, meaning page++
> would still work. So when MAX_ORDER - 1 crosses sections, additional code would be
> needed instead of simple pfn++. Is there anything I am missing?
I think there are two cases when talking about MAX_ORDER and memory holes:
1. Hole with a valid memmap: the memmap is initialize to PageReserved()
and the pages are not given to the buddy. pfn_valid() and
pfn_to_page() works as expected.
2. Hole without a valid memmam: we have that CONFIG_HOLES_IN_ZONE thing
already, see include/linux/mmzone.h. pfn_valid_within() checks are
required. Doesn't win a beauty contest, but gets the job done in
existing setups that seem to care.
"If it is possible to have holes within a MAX_ORDER_NR_PAGES, then we
need to check pfn validity within that MAX_ORDER_NR_PAGES block.
pfn_valid_within() should be used in this case; we optimise this away
when we have no holes within a MAX_ORDER_NR_PAGES block."
CONFIG_HOLES_IN_ZONE is just a bad name for this.
(increasing the section size implies that we waste more memory for the
memmap in holes. increasing MAX_ORDER means that we might have to deal
with holes within MAX_ORDER chunks)
We don't have too many pfn_valid_within() checks. I wonder if we could
add something that is optimized for "holes are a power of two and
properly aligned", because pfn_valid_within() right not deals with holes
of any kind which makes it somewhat inefficient IIRC.
>
> BTW, to test a system with memory holes, do you know is there an easy of adding
> random memory holes to an x86_64 VM, which can help reveal potential missing pieces
> in the code? Changing BIOS-e820 table might be one way, but I have no idea on
> how to do it on QEMU.
It might not be very easy that way. But I heard that some arm64 systems
have crazy memory layouts -- maybe there, it's easier to get something
nasty running? :)
https://lkml.kernel.org/r/YJpEwF2cGjS5mKma@kernel.org
I remember there was a way to define the e820 completely on kernel
cmdline, but I might be wrong ...
--
Thanks,
David / dhildenb
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