Automatic merge of 'next-test' into merge-test (2026-03-17 14:03)

Author: maddy-kerneldev

Documentation/rust/arch-support.rst

@@ -18,6 +18,7 @@ Architecture   Level of support  Constraints
 ``arm``        Maintained        ARMv7 Little Endian only.
 ``arm64``      Maintained        Little Endian only.
 ``loongarch``  Maintained        \-
+``powerpc``    Maintained        64-bit Little Endian. 32-bit Big Endian.
 ``riscv``      Maintained        ``riscv64`` and LLVM/Clang only.
 ``um``         Maintained        \-
 ``x86``        Maintained        ``x86_64`` only.

arch/powerpc/Kconfig

@@ -284,6 +284,8 @@ config PPC
 	select HAVE_REGS_AND_STACK_ACCESS_API
 	select HAVE_RELIABLE_STACKTRACE
 	select HAVE_RSEQ
+	select HAVE_RUST			if PPC32
+	select HAVE_RUST			if PPC64 && CPU_LITTLE_ENDIAN
 	select HAVE_SAMPLE_FTRACE_DIRECT	if HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
 	select HAVE_SAMPLE_FTRACE_DIRECT_MULTI	if HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
 	select HAVE_SETUP_PER_CPU_AREA		if PPC64

arch/powerpc/Makefile

@@ -61,6 +61,13 @@ else
 KBUILD_LDFLAGS_MODULE += $(objtree)/arch/powerpc/lib/crtsavres.o
 endif
 
+ifdef CONFIG_PPC64
+KBUILD_RUSTFLAGS	+= --target=powerpc64le-unknown-linux-gnu
+KBUILD_RUSTFLAGS	+= -Ctarget-feature=-mma,-vsx,-hard-float,-altivec
+else
+KBUILD_RUSTFLAGS	+= --target=powerpc-unknown-linux-gnu
+endif
+
 ifdef CONFIG_CPU_LITTLE_ENDIAN
 KBUILD_CPPFLAGS	+= -mlittle-endian
 KBUILD_LDFLAGS	+= -EL

arch/powerpc/include/asm/book3s/64/pgtable.h

@@ -107,8 +107,8 @@
  * in here, on radix we expect them to be zero.
  */
 #define _HPAGE_CHG_MASK (PTE_RPN_MASK | _PAGE_HPTEFLAGS | _PAGE_DIRTY | \
-			 _PAGE_ACCESSED | H_PAGE_THP_HUGE | _PAGE_PTE | \
-			 _PAGE_SOFT_DIRTY)
+			 _PAGE_ACCESSED | H_PAGE_THP_HUGE | _PAGE_SPECIAL | \
+			 _PAGE_PTE | _PAGE_SOFT_DIRTY)
 /*
  * user access blocked by key
  */
@@ -1313,12 +1313,27 @@ static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm,
 {
 	pmd_t old_pmd;
 
+	/*
+	 * Non-present PMDs can be migration entries or device-private THP
+	 * entries. This can happen at 2 places:
+	 * - When the address space is being unmapped zap_huge_pmd(), and we
+	 *   encounter non-present pmds.
+	 * - migrate_vma_collect_huge_pmd() could calls this during migration
+	 *   of device-private pmd entries.
+	 */
+	if (!pmd_present(*pmdp)) {
+		old_pmd = READ_ONCE(*pmdp);
+		pmd_clear(pmdp);
+		goto out;
+	}
+
 	if (radix_enabled()) {
 		old_pmd = radix__pmdp_huge_get_and_clear(mm, addr, pmdp);
 	} else {
 		old_pmd = hash__pmdp_huge_get_and_clear(mm, addr, pmdp);
 	}
 
+out:
 	page_table_check_pmd_clear(mm, addr, old_pmd);
 
 	return old_pmd;
@@ -1400,7 +1415,6 @@ static inline bool arch_needs_pgtable_deposit(void)
 		return false;
 	return true;
 }
-extern void serialize_against_pte_lookup(struct mm_struct *mm);
 
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 

arch/powerpc/include/asm/book3s/64/tlbflush-radix.h

@@ -92,7 +92,6 @@ extern void radix__flush_tlb_page_psize(struct mm_struct *mm, unsigned long vmad
 #define radix__flush_tlb_page(vma,addr)	radix__local_flush_tlb_page(vma,addr)
 #define radix__flush_tlb_page_psize(mm,addr,p) radix__local_flush_tlb_page_psize(mm,addr,p)
 #endif
-extern void radix__flush_tlb_pwc(struct mmu_gather *tlb, unsigned long addr);
 extern void radix__flush_tlb_collapsed_pmd(struct mm_struct *mm, unsigned long addr);
 extern void radix__flush_tlb_all(void);
 

arch/powerpc/include/asm/jump_label.h

@@ -15,14 +15,20 @@
 #define JUMP_ENTRY_TYPE		stringify_in_c(FTR_ENTRY_LONG)
 #define JUMP_LABEL_NOP_SIZE	4
 
+#define JUMP_TABLE_ENTRY(key, label)			\
+	".pushsection __jump_table,  \"aw\"	\n\t"	\
+	".long 1b - ., " label " - .		\n\t"	\
+	JUMP_ENTRY_TYPE key " - .		\n\t"	\
+	".popsection 				\n\t"
+
+#define ARCH_STATIC_BRANCH_ASM(key, label)		\
+	"1:	nop				\n\t"	\
+	JUMP_TABLE_ENTRY(key,label)
+
 static __always_inline bool arch_static_branch(struct static_key *key, bool branch)
 {
-	asm goto("1:\n\t"
-		 "nop # arch_static_branch\n\t"
-		 ".pushsection __jump_table,  \"aw\"\n\t"
-		 ".long 1b - ., %l[l_yes] - .\n\t"
-		 JUMP_ENTRY_TYPE "%c0 - .\n\t"
-		 ".popsection \n\t"
+	asm goto(
+		 ARCH_STATIC_BRANCH_ASM("%c0", "%l[l_yes]")
 		 : :  "i" (&((char *)key)[branch]) : : l_yes);
 
 	return false;
@@ -34,10 +40,7 @@ static __always_inline bool arch_static_branch_jump(struct static_key *key, bool
 {
 	asm goto("1:\n\t"
 		 "b %l[l_yes] # arch_static_branch_jump\n\t"
-		 ".pushsection __jump_table,  \"aw\"\n\t"
-		 ".long 1b - ., %l[l_yes] - .\n\t"
-		 JUMP_ENTRY_TYPE "%c0 - .\n\t"
-		 ".popsection \n\t"
+		 JUMP_TABLE_ENTRY("%c0", "%l[l_yes]")
 		 : :  "i" (&((char *)key)[branch]) : : l_yes);
 
 	return false;

arch/powerpc/kernel/setup-common.c

@@ -865,6 +865,10 @@ static __init void print_system_info(void)
 		cur_cpu_spec->cpu_user_features,
 		cur_cpu_spec->cpu_user_features2);
 	pr_info("mmu_features      = 0x%08x\n", cur_cpu_spec->mmu_features);
+	pr_info("  possible        = 0x%016lx\n",
+		(unsigned long)MMU_FTRS_POSSIBLE);
+	pr_info("  always          = 0x%016lx\n",
+		(unsigned long)MMU_FTRS_ALWAYS);
 #ifdef CONFIG_PPC64
 	pr_info("firmware_features = 0x%016lx\n", powerpc_firmware_features);
 #ifdef CONFIG_PPC_BOOK3S

arch/powerpc/mm/book3s64/hash_pgtable.c

@@ -221,6 +221,27 @@ unsigned long hash__pmd_hugepage_update(struct mm_struct *mm, unsigned long addr
 	return old;
 }
 
+static void do_nothing(void *arg)
+{
+
+}
+
+/*
+ * Serialize against __find_linux_pte() which does lock-less
+ * lookup in page tables with local interrupts disabled. For huge pages
+ * it casts pmd_t to pte_t. Since format of pte_t is different from
+ * pmd_t we want to prevent transit from pmd pointing to page table
+ * to pmd pointing to huge page (and back) while interrupts are disabled.
+ * We clear pmd to possibly replace it with page table pointer in
+ * different code paths. So make sure we wait for the parallel
+ * __find_linux_pte() to finish.
+ */
+static void serialize_against_pte_lookup(struct mm_struct *mm)
+{
+	smp_mb();
+	smp_call_function_many(mm_cpumask(mm), do_nothing, mm, 1);
+}
+
 pmd_t hash__pmdp_collapse_flush(struct vm_area_struct *vma, unsigned long address,
 			    pmd_t *pmdp)
 {

arch/powerpc/mm/book3s64/internal.h

@@ -31,6 +31,4 @@ static inline bool slb_preload_disabled(void)
 
 void hpt_do_stress(unsigned long ea, unsigned long hpte_group);
 
-void exit_lazy_flush_tlb(struct mm_struct *mm, bool always_flush);
-
 #endif /* ARCH_POWERPC_MM_BOOK3S64_INTERNAL_H */

arch/powerpc/mm/book3s64/pgtable.c

@@ -23,8 +23,6 @@
 #include <mm/mmu_decl.h>
 #include <trace/events/thp.h>
 
-#include "internal.h"
-
 struct mmu_psize_def mmu_psize_defs[MMU_PAGE_COUNT];
 EXPORT_SYMBOL_GPL(mmu_psize_defs);
 
@@ -150,31 +148,6 @@ void set_pud_at(struct mm_struct *mm, unsigned long addr,
 	return set_pte_at_unchecked(mm, addr, pudp_ptep(pudp), pud_pte(pud));
 }
 
-static void do_serialize(void *arg)
-{
-	/* We've taken the IPI, so try to trim the mask while here */
-	if (radix_enabled()) {
-		struct mm_struct *mm = arg;
-		exit_lazy_flush_tlb(mm, false);
-	}
-}
-
-/*
- * Serialize against __find_linux_pte() which does lock-less
- * lookup in page tables with local interrupts disabled. For huge pages
- * it casts pmd_t to pte_t. Since format of pte_t is different from
- * pmd_t we want to prevent transit from pmd pointing to page table
- * to pmd pointing to huge page (and back) while interrupts are disabled.
- * We clear pmd to possibly replace it with page table pointer in
- * different code paths. So make sure we wait for the parallel
- * __find_linux_pte() to finish.
- */
-void serialize_against_pte_lookup(struct mm_struct *mm)
-{
-	smp_mb();
-	smp_call_function_many(mm_cpumask(mm), do_serialize, mm, 1);
-}
-
 /*
  * We use this to invalidate a pmdp entry before switching from a
  * hugepte to regular pmd entry.
@@ -209,16 +182,21 @@ pmd_t pmdp_huge_get_and_clear_full(struct vm_area_struct *vma,
 				   unsigned long addr, pmd_t *pmdp, int full)
 {
 	pmd_t pmd;
+	bool was_present = pmd_present(*pmdp);
+
 	VM_BUG_ON(addr & ~HPAGE_PMD_MASK);
-	VM_BUG_ON((pmd_present(*pmdp) && !pmd_trans_huge(*pmdp)) ||
-		   !pmd_present(*pmdp));
+	VM_BUG_ON(was_present && !pmd_trans_huge(*pmdp));
+	/*
+	 * Check pmdp_huge_get_and_clear() for non-present pmd case.
+	 */
 	pmd = pmdp_huge_get_and_clear(vma->vm_mm, addr, pmdp);
 	/*
 	 * if it not a fullmm flush, then we can possibly end up converting
 	 * this PMD pte entry to a regular level 0 PTE by a parallel page fault.
-	 * Make sure we flush the tlb in this case.
+	 * Make sure we flush the tlb in this case. TLB flush not needed for
+	 * non-present case.
 	 */
-	if (!full)
+	if (was_present && !full)
 		flush_pmd_tlb_range(vma, addr, addr + HPAGE_PMD_SIZE);
 	return pmd;
 }