The patch titled
Subject: arm64: mte: convert gcr_user into an exclude mask
has been added to the -mm tree. Its filename is
arm64-mte-convert-gcr_user-into-an-exclude-mask.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/arm64-mte-convert-gcr_user-into-an-exclude-mask.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/arm64-mte-convert-gcr_user-into-an-exclude-mask.patch
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------------------------------------------------------
From: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>
Subject: arm64: mte: convert gcr_user into an exclude mask
The gcr_user mask is a per thread mask that represents the tags that are
excluded from random generation when the Memory Tagging Extension is
present and an 'irg' instruction is invoked.
gcr_user affects the behavior on EL0 only.
Currently that mask is an include mask and it is controlled by the user
via prctl() while GCR_EL1 accepts an exclude mask.
Convert the include mask into an exclude one to make it easier the
register setting.
Note: This change will affect gcr_kernel (for EL1) introduced with a
future patch.
Link: https://lkml.kernel.org/r/a5242d8eaa3c305c068aa531755eb78d0be5ffd3.1605046192.git.andreyknvl@xxxxxxxxxx
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>
Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Cc: Branislav Rankov <Branislav.Rankov@xxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Evgenii Stepanov <eugenis@xxxxxxxxxx>
Cc: Kevin Brodsky <kevin.brodsky@xxxxxxx>
Cc: Marco Elver <elver@xxxxxxxxxx>
Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/arm64/include/asm/processor.h | 2 -
arch/arm64/kernel/mte.c | 29 +++++++++++++--------------
2 files changed, 16 insertions(+), 15 deletions(-)
--- a/arch/arm64/include/asm/processor.h~arm64-mte-convert-gcr_user-into-an-exclude-mask
+++ a/arch/arm64/include/asm/processor.h
@@ -154,7 +154,7 @@ struct thread_struct {
#endif
#ifdef CONFIG_ARM64_MTE
u64 sctlr_tcf0;
- u64 gcr_user_incl;
+ u64 gcr_user_excl;
#endif
};
--- a/arch/arm64/kernel/mte.c~arm64-mte-convert-gcr_user-into-an-exclude-mask
+++ a/arch/arm64/kernel/mte.c
@@ -156,23 +156,22 @@ static void set_sctlr_el1_tcf0(u64 tcf0)
preempt_enable();
}
-static void update_gcr_el1_excl(u64 incl)
+static void update_gcr_el1_excl(u64 excl)
{
- u64 excl = ~incl & SYS_GCR_EL1_EXCL_MASK;
/*
- * Note that 'incl' is an include mask (controlled by the user via
- * prctl()) while GCR_EL1 accepts an exclude mask.
+ * Note that the mask controlled by the user via prctl() is an
+ * include while GCR_EL1 accepts an exclude mask.
* No need for ISB since this only affects EL0 currently, implicit
* with ERET.
*/
sysreg_clear_set_s(SYS_GCR_EL1, SYS_GCR_EL1_EXCL_MASK, excl);
}
-static void set_gcr_el1_excl(u64 incl)
+static void set_gcr_el1_excl(u64 excl)
{
- current->thread.gcr_user_incl = incl;
- update_gcr_el1_excl(incl);
+ current->thread.gcr_user_excl = excl;
+ update_gcr_el1_excl(excl);
}
void flush_mte_state(void)
@@ -187,7 +186,7 @@ void flush_mte_state(void)
/* disable tag checking */
set_sctlr_el1_tcf0(SCTLR_EL1_TCF0_NONE);
/* reset tag generation mask */
- set_gcr_el1_excl(0);
+ set_gcr_el1_excl(SYS_GCR_EL1_EXCL_MASK);
}
void mte_thread_switch(struct task_struct *next)
@@ -198,7 +197,7 @@ void mte_thread_switch(struct task_struc
/* avoid expensive SCTLR_EL1 accesses if no change */
if (current->thread.sctlr_tcf0 != next->thread.sctlr_tcf0)
update_sctlr_el1_tcf0(next->thread.sctlr_tcf0);
- update_gcr_el1_excl(next->thread.gcr_user_incl);
+ update_gcr_el1_excl(next->thread.gcr_user_excl);
}
void mte_suspend_exit(void)
@@ -206,13 +205,14 @@ void mte_suspend_exit(void)
if (!system_supports_mte())
return;
- update_gcr_el1_excl(current->thread.gcr_user_incl);
+ update_gcr_el1_excl(current->thread.gcr_user_excl);
}
long set_mte_ctrl(struct task_struct *task, unsigned long arg)
{
u64 tcf0;
- u64 gcr_incl = (arg & PR_MTE_TAG_MASK) >> PR_MTE_TAG_SHIFT;
+ u64 gcr_excl = ~((arg & PR_MTE_TAG_MASK) >> PR_MTE_TAG_SHIFT) &
+ SYS_GCR_EL1_EXCL_MASK;
if (!system_supports_mte())
return 0;
@@ -233,10 +233,10 @@ long set_mte_ctrl(struct task_struct *ta
if (task != current) {
task->thread.sctlr_tcf0 = tcf0;
- task->thread.gcr_user_incl = gcr_incl;
+ task->thread.gcr_user_excl = gcr_excl;
} else {
set_sctlr_el1_tcf0(tcf0);
- set_gcr_el1_excl(gcr_incl);
+ set_gcr_el1_excl(gcr_excl);
}
return 0;
@@ -245,11 +245,12 @@ long set_mte_ctrl(struct task_struct *ta
long get_mte_ctrl(struct task_struct *task)
{
unsigned long ret;
+ u64 incl = ~task->thread.gcr_user_excl & SYS_GCR_EL1_EXCL_MASK;
if (!system_supports_mte())
return 0;
- ret = task->thread.gcr_user_incl << PR_MTE_TAG_SHIFT;
+ ret = incl << PR_MTE_TAG_SHIFT;
switch (task->thread.sctlr_tcf0) {
case SCTLR_EL1_TCF0_NONE:
_
Patches currently in -mm which might be from vincenzo.frascino@xxxxxxx are
mm-vmalloc-fix-kasan-shadow-poisoning-size.patch
arm64-enable-armv85-a-asm-arch-option.patch
arm64-mte-add-in-kernel-mte-helpers.patch
arm64-mte-reset-the-page-tag-in-page-flags.patch
arm64-mte-add-in-kernel-tag-fault-handler.patch
arm64-kasan-allow-enabling-in-kernel-mte.patch
arm64-mte-convert-gcr_user-into-an-exclude-mask.patch
arm64-mte-switch-gcr_el1-in-kernel-entry-and-exit.patch
kasan-mm-untag-page-address-in-free_reserved_area.patch
kselftest-arm64-check-gcr_el1-after-context-switch.patch
