From 428e106ae1ad4e45d3fd6978a753db475d0d0ec9 Mon Sep 17 00:00:00 2001
From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Date: Sun, 12 Mar 2023 14:26:00 +0300
Subject: mm: Introduce untagged_addr_remote()

untagged_addr() removes tags/metadata from the address and brings it to
the canonical form. The helper is implemented on arm64 and sparc. Both of
them do untagging based on global rules.

However, Linear Address Masking (LAM) on x86 introduces per-process
settings for untagging. As a result, untagged_addr() is now only
suitable for untagging addresses for the current proccess.

The new helper untagged_addr_remote() has to be used when the address
targets remote process. It requires the mmap lock for target mm to be
taken.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Alexander Potapenko <glider@google.com>
Link: https://lore.kernel.org/all/20230312112612.31869-6-kirill.shutemov%40linux.intel.com
---
 arch/sparc/include/asm/uaccess_64.h | 2 ++
 1 file changed, 2 insertions(+)

(limited to 'arch/sparc/include')

diff --git a/arch/sparc/include/asm/uaccess_64.h b/arch/sparc/include/asm/uaccess_64.h
index 94266a5c5b04..b825a5dd0210 100644
--- a/arch/sparc/include/asm/uaccess_64.h
+++ b/arch/sparc/include/asm/uaccess_64.h
@@ -8,8 +8,10 @@
 
 #include <linux/compiler.h>
 #include <linux/string.h>
+#include <linux/mm_types.h>
 #include <asm/asi.h>
 #include <asm/spitfire.h>
+#include <asm/pgtable.h>
 
 #include <asm/processor.h>
 #include <asm-generic/access_ok.h>
-- 
cgit v1.2.3


From f7d304343b9d2456ffba23b99d2345408251ea45 Mon Sep 17 00:00:00 2001
From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Date: Sun, 12 Mar 2023 14:26:04 +0300
Subject: mm: Expose untagging mask in /proc/$PID/status

Add a line in /proc/$PID/status to report untag_mask. It can be
used to find out LAM status of the process from the outside. It is
useful for debuggers.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Alexander Potapenko <glider@google.com>
Link: https://lore.kernel.org/all/20230312112612.31869-10-kirill.shutemov%40linux.intel.com
---
 arch/sparc/include/asm/mmu_context_64.h | 6 ++++++
 1 file changed, 6 insertions(+)

(limited to 'arch/sparc/include')

diff --git a/arch/sparc/include/asm/mmu_context_64.h b/arch/sparc/include/asm/mmu_context_64.h
index 7a8380c63aab..799e797c5cdd 100644
--- a/arch/sparc/include/asm/mmu_context_64.h
+++ b/arch/sparc/include/asm/mmu_context_64.h
@@ -185,6 +185,12 @@ static inline void finish_arch_post_lock_switch(void)
 	}
 }
 
+#define mm_untag_mask mm_untag_mask
+static inline unsigned long mm_untag_mask(struct mm_struct *mm)
+{
+       return -1UL >> adi_nbits();
+}
+
 #include <asm-generic/mmu_context.h>
 
 #endif /* !(__ASSEMBLY__) */
-- 
cgit v1.2.3