Merge tag 'x86_shstk_for_6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 shadow stack support from Dave Hansen:
 "This is the long awaited x86 shadow stack support, part of Intel's
  Control-flow Enforcement Technology (CET).

  CET consists of two related security features: shadow stacks and
  indirect branch tracking. This series implements just the shadow stack
  part of this feature, and just for userspace.

  The main use case for shadow stack is providing protection against
  return oriented programming attacks. It works by maintaining a
  secondary (shadow) stack using a special memory type that has
  protections against modification. When executing a CALL instruction,
  the processor pushes the return address to both the normal stack and
  to the special permission shadow stack. Upon RET, the processor pops
  the shadow stack copy and compares it to the normal stack copy.

  For more information, refer to the links below for the earlier
  versions of this patch set"

Link: https://lore.kernel.org/lkml/20220130211838.8382-1-rick.p.edgecombe@intel.com/
Link: https://lore.kernel.org/lkml/20230613001108.3040476-1-rick.p.edgecombe@intel.com/

* tag 'x86_shstk_for_6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (47 commits)
  x86/shstk: Change order of __user in type
  x86/ibt: Convert IBT selftest to asm
  x86/shstk: Don't retry vm_munmap() on -EINTR
  x86/kbuild: Fix Documentation/ reference
  x86/shstk: Move arch detail comment out of core mm
  x86/shstk: Add ARCH_SHSTK_STATUS
  x86/shstk: Add ARCH_SHSTK_UNLOCK
  x86: Add PTRACE interface for shadow stack
  selftests/x86: Add shadow stack test
  x86/cpufeatures: Enable CET CR4 bit for shadow stack
  x86/shstk: Wire in shadow stack interface
  x86: Expose thread features in /proc/$PID/status
  x86/shstk: Support WRSS for userspace
  x86/shstk: Introduce map_shadow_stack syscall
  x86/shstk: Check that signal frame is shadow stack mem
  x86/shstk: Check that SSP is aligned on sigreturn
  x86/shstk: Handle signals for shadow stack
  x86/shstk: Introduce routines modifying shstk
  x86/shstk: Handle thread shadow stack
  x86/shstk: Add user-mode shadow stack support
  ...

4 files changed, 6 insertions, 5 deletions

diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 661b6de69c27..ae29e4392664 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -127,6 +127,7 @@ config S390
 	select ARCH_WANTS_NO_INSTR
 	select ARCH_WANT_DEFAULT_BPF_JIT
 	select ARCH_WANT_IPC_PARSE_VERSION
+	select ARCH_WANT_KERNEL_PMD_MKWRITE
 	select ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP
 	select BUILDTIME_TABLE_SORT
 	select CLONE_BACKWARDS2
diff --git a/arch/s390/include/asm/hugetlb.h b/arch/s390/include/asm/hugetlb.h
index ccdbccfde148..f07267875a19 100644
--- a/arch/s390/include/asm/hugetlb.h
+++ b/arch/s390/include/asm/hugetlb.h
@@ -104,7 +104,7 @@ static inline int huge_pte_dirty(pte_t pte)
 
 static inline pte_t huge_pte_mkwrite(pte_t pte)
 {
-	return pte_mkwrite(pte);
+	return pte_mkwrite_novma(pte);
 }
 
 static inline pte_t huge_pte_mkdirty(pte_t pte)
diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
index d28d2e5e68ee..fb3ee7758b76 100644
--- a/arch/s390/include/asm/pgtable.h
+++ b/arch/s390/include/asm/pgtable.h
@@ -1001,7 +1001,7 @@ static inline pte_t pte_wrprotect(pte_t pte)
 	return set_pte_bit(pte, __pgprot(_PAGE_PROTECT));
 }
 
-static inline pte_t pte_mkwrite(pte_t pte)
+static inline pte_t pte_mkwrite_novma(pte_t pte)
 {
 	pte = set_pte_bit(pte, __pgprot(_PAGE_WRITE));
 	if (pte_val(pte) & _PAGE_DIRTY)
@@ -1498,7 +1498,7 @@ static inline pmd_t pmd_wrprotect(pmd_t pmd)
 	return set_pmd_bit(pmd, __pgprot(_SEGMENT_ENTRY_PROTECT));
 }
 
-static inline pmd_t pmd_mkwrite(pmd_t pmd)
+static inline pmd_t pmd_mkwrite_novma(pmd_t pmd)
 {
 	pmd = set_pmd_bit(pmd, __pgprot(_SEGMENT_ENTRY_WRITE));
 	if (pmd_val(pmd) & _SEGMENT_ENTRY_DIRTY)
diff --git a/arch/s390/mm/pageattr.c b/arch/s390/mm/pageattr.c
index ca5a418c58a8..e5ec76271b16 100644
--- a/arch/s390/mm/pageattr.c
+++ b/arch/s390/mm/pageattr.c
@@ -98,7 +98,7 @@ static int walk_pte_level(pmd_t *pmdp, unsigned long addr, unsigned long end,
 		if (flags & SET_MEMORY_RO)
 			new = pte_wrprotect(new);
 		else if (flags & SET_MEMORY_RW)
-			new = pte_mkwrite(pte_mkdirty(new));
+			new = pte_mkwrite_novma(pte_mkdirty(new));
 		if (flags & SET_MEMORY_NX)
 			new = set_pte_bit(new, __pgprot(_PAGE_NOEXEC));
 		else if (flags & SET_MEMORY_X)
@@ -156,7 +156,7 @@ static void modify_pmd_page(pmd_t *pmdp, unsigned long addr,
 	if (flags & SET_MEMORY_RO)
 		new = pmd_wrprotect(new);
 	else if (flags & SET_MEMORY_RW)
-		new = pmd_mkwrite(pmd_mkdirty(new));
+		new = pmd_mkwrite_novma(pmd_mkdirty(new));
 	if (flags & SET_MEMORY_NX)
 		new = set_pmd_bit(new, __pgprot(_SEGMENT_ENTRY_NOEXEC));
 	else if (flags & SET_MEMORY_X)