From: Deepak Sharma <deepak.sharma(a)amd.com>
commit a8fb40966f19ff81520d9ccf8f7e2b95201368b8 upstream.
All Zen or newer CPU which support C3 shares cache. Its not necessary to
flush the caches in software before entering C3. This will cause drop in
performance for the cores which share some caches. ARB_DIS is not used
with current AMD C state implementation. So set related flags correctly.
Signed-off-by: Deepak Sharma <deepak.sharma(a)amd.com>
Acked-by: Thomas Gleixner <tglx(a)linutronix.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki(a)intel.com>
Signed-off-by: Guilherme G. Piccoli <gpiccoli(a)igalia.com>
---
Hi folks, this is a very simple optimization that might be read
as a fix IMO, since it's setting the flags correctly for the Zen CPUs.
It was built/boot tested in the Steam Deck.
The backport for stable was a suggestion from Greg [0], so lemme
know if any of you see an issue with that, or if we should target
other stable versions (or less versions, maybe only 5.15).
Cheers,
Guilherme
[0] https://github.com/ValveSoftware/SteamOS/issues/954#issuecomment-1368182597
arch/x86/kernel/acpi/cstate.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/arch/x86/kernel/acpi/cstate.c b/arch/x86/kernel/acpi/cstate.c
index 49ae4e1ac9cd..d28d43d774a2 100644
--- a/arch/x86/kernel/acpi/cstate.c
+++ b/arch/x86/kernel/acpi/cstate.c
@@ -79,6 +79,21 @@ void acpi_processor_power_init_bm_check(struct acpi_processor_flags *flags,
*/
flags->bm_control = 0;
}
+ if (c->x86_vendor == X86_VENDOR_AMD && c->x86 >= 0x17) {
+ /*
+ * For all AMD Zen or newer CPUs that support C3, caches
+ * should not be flushed by software while entering C3
+ * type state. Set bm->check to 1 so that kernel doesn't
+ * need to execute cache flush operation.
+ */
+ flags->bm_check = 1;
+ /*
+ * In current AMD C state implementation ARB_DIS is no longer
+ * used. So set bm_control to zero to indicate ARB_DIS is not
+ * required while entering C3 type state.
+ */
+ flags->bm_control = 0;
+ }
}
EXPORT_SYMBOL(acpi_processor_power_init_bm_check);
--
2.39.0
Currently, when resetting the USB modem via AT commands, the modem is
no longer re-connected.
This problem is caused by the incorrect description of the USB_OTG2_OC
pad. It should have pull-up enabled, hysteresis enabled and the
property 'over-current-active-low' should be passed.
With this change, the USB modem can be successfully re-connected
after a reset.
Cc: stable(a)vger.kernel.org
Fixes: 9ac0ae97e349 ("ARM: dts: imx7d-smegw01: Add support for i.MX7D SMEGW01 board")
Signed-off-by: Fabio Estevam <festevam(a)denx.de>
---
arch/arm/boot/dts/imx7d-smegw01.dts | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/arm/boot/dts/imx7d-smegw01.dts b/arch/arm/boot/dts/imx7d-smegw01.dts
index 546268b8d0b1..c0f00f5db11e 100644
--- a/arch/arm/boot/dts/imx7d-smegw01.dts
+++ b/arch/arm/boot/dts/imx7d-smegw01.dts
@@ -198,6 +198,7 @@ &usbotg1 {
&usbotg2 {
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_usbotg2>;
+ over-current-active-low;
dr_mode = "host";
status = "okay";
};
@@ -374,7 +375,7 @@ MX7D_PAD_LPSR_GPIO1_IO05__GPIO1_IO5 0x04
pinctrl_usbotg2: usbotg2grp {
fsl,pins = <
- MX7D_PAD_UART3_RTS_B__USB_OTG2_OC 0x04
+ MX7D_PAD_UART3_RTS_B__USB_OTG2_OC 0x5c
>;
};
--
2.25.1
The previous algorithm was pretty broken.
- The inner loop had a '(m > m_max)' condition, and the value of 'm'
would increase in each iteration;
- Each iteration would actually multiply 'm' by two, so it is not needed
to re-compute the whole equation at each iteration;
- It would loop until (m & 1) == 0, which means it would loop at most
once.
- The outer loop would divide the 'n' value by two at the end of each
iteration. This meant that for a 12 MHz parent clock and a 1.2 GHz
requested clock, it would first try n=12, then n=6, then n=3, then
n=1, none of which would work; the only valid value is n=2 in this
case.
Simplify this algorithm with a single for loop, which decrements 'n'
after each iteration, addressing all of the above problems.
Fixes: bdbfc029374f ("clk: ingenic: Add support for the JZ4760")
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Paul Cercueil <paul(a)crapouillou.net>
---
drivers/clk/ingenic/jz4760-cgu.c | 18 ++++++++----------
1 file changed, 8 insertions(+), 10 deletions(-)
diff --git a/drivers/clk/ingenic/jz4760-cgu.c b/drivers/clk/ingenic/jz4760-cgu.c
index ecd395ac8a28..e407f00bd594 100644
--- a/drivers/clk/ingenic/jz4760-cgu.c
+++ b/drivers/clk/ingenic/jz4760-cgu.c
@@ -58,7 +58,7 @@ jz4760_cgu_calc_m_n_od(const struct ingenic_cgu_pll_info *pll_info,
unsigned long rate, unsigned long parent_rate,
unsigned int *pm, unsigned int *pn, unsigned int *pod)
{
- unsigned int m, n, od, m_max = (1 << pll_info->m_bits) - 2;
+ unsigned int m, n, od, m_max = (1 << pll_info->m_bits) - 1;
/* The frequency after the N divider must be between 1 and 50 MHz. */
n = parent_rate / (1 * MHZ);
@@ -66,19 +66,17 @@ jz4760_cgu_calc_m_n_od(const struct ingenic_cgu_pll_info *pll_info,
/* The N divider must be >= 2. */
n = clamp_val(n, 2, 1 << pll_info->n_bits);
- for (;; n >>= 1) {
- od = (unsigned int)-1;
+ rate /= MHZ;
+ parent_rate /= MHZ;
- do {
- m = (rate / MHZ) * (1 << ++od) * n / (parent_rate / MHZ);
- } while ((m > m_max || m & 1) && (od < 4));
-
- if (od < 4 && m >= 4 && m <= m_max)
- break;
+ for (m = m_max; m >= m_max && n >= 2; n--) {
+ m = rate * n / parent_rate;
+ od = m & 1;
+ m <<= od;
}
*pm = m;
- *pn = n;
+ *pn = n + 1;
*pod = 1 << od;
}
--
2.35.1
In commit 34488399fa08 ("mm/madvise: add file and shmem support to
MADV_COLLAPSE") we make the following change to find_pmd_or_thp_or_none():
- if (!pmd_present(pmde))
- return SCAN_PMD_NULL;
+ if (pmd_none(pmde))
+ return SCAN_PMD_NONE;
This was for-use by MADV_COLLAPSE file/shmem codepaths, where MADV_COLLAPSE
might identify a pte-mapped hugepage, only to have khugepaged race-in, free
the pte table, and clear the pmd. Such codepaths include:
A) If we find a suitably-aligned compound page of order HPAGE_PMD_ORDER
already in the pagecache.
B) In retract_page_tables(), if we fail to grab mmap_lock for the target
mm/address.
In these cases, collapse_pte_mapped_thp() really does expect a none (not
just !present) pmd, and we want to suitably identify that case separate
from the case where no pmd is found, or it's a bad-pmd (of course, many
things could happen once we drop mmap_lock, and the pmd could plausibly
undergo multiple transitions due to intervening fault, split, etc).
Regardless, the code is prepared install a huge-pmd only when the existing
pmd entry is either a genuine pte-table-mapping-pmd, or the none-pmd.
However, the commit introduces a logical hole; namely, that we've allowed
!none- && !huge- && !bad-pmds to be classified as genuine
pte-table-mapping-pmds. One such example that could leak through are swap
entries. The pmd values aren't checked again before use in
pte_offset_map_lock(), which is expecting nothing less than a genuine
pte-table-mapping-pmd.
We want to put back the !pmd_present() check (below the pmd_none() check),
but need to be careful to deal with subtleties in pmd transitions and
treatments by various arch.
The issue is that __split_huge_pmd_locked() temporarily clears the present
bit (or otherwise marks the entry as invalid), but pmd_present()
and pmd_trans_huge() still need to return true while the pmd is in this
transitory state. For example, x86's pmd_present() also checks the
_PAGE_PSE , riscv's version also checks the _PAGE_LEAF bit, and arm64 also
checks a PMD_PRESENT_INVALID bit.
Covering all 4 cases for x86 (all checks done on the same pmd value):
1) pmd_present() && pmd_trans_huge()
All we actually know here is that the PSE bit is set. Either:
a) We aren't racing with __split_huge_page(), and PRESENT or PROTNONE
is set.
=> huge-pmd
b) We are currently racing with __split_huge_page(). The danger here
is that we proceed as-if we have a huge-pmd, but really we are
looking at a pte-mapping-pmd. So, what is the risk of this
danger?
The only relevant path is:
madvise_collapse() -> collapse_pte_mapped_thp()
Where we might just incorrectly report back "success", when really
the memory isn't pmd-backed. This is fine, since split could
happen immediately after (actually) successful madvise_collapse().
So, it should be safe to just assume huge-pmd here.
2) pmd_present() && !pmd_trans_huge()
Either:
a) PSE not set and either PRESENT or PROTNONE is.
=> pte-table-mapping pmd (or PROT_NONE)
b) devmap. This routine can be called immediately after
unlocking/locking mmap_lock -- or called with no locks held (see
khugepaged_scan_mm_slot()), so previous VMA checks have since been
invalidated.
3) !pmd_present() && pmd_trans_huge()
Not possible.
4) !pmd_present() && !pmd_trans_huge()
Neither PRESENT nor PROTNONE set
=> not present
I've checked all archs that implement pmd_trans_huge() (arm64, riscv,
powerpc, longarch, x86, mips, s390) and this logic roughly translates
(though devmap treatment is unique to x86 and powerpc, and (3) doesn't
necessarily hold in general -- but that doesn't matter since !pmd_present()
always takes failure path).
Also, add a comment above find_pmd_or_thp_or_none() to help future
travelers reason about the validity of the code; namely, the possible
mutations that might happen out from under us, depending on how
mmap_lock is held (if at all).
Fixes: 34488399fa08 ("mm/madvise: add file and shmem support to MADV_COLLAPSE")
Reported-by: Hugh Dickins <hughd(a)google.com>
Signed-off-by: Zach O'Keefe <zokeefe(a)google.com>
Cc: stable(a)vger.kernel.org
---
Request that this be pulled into stable since it's theoretically
possible (though I have no reproducer) that while mmap_lock is dropped,
racing thp migration installs a pmd migration entry which then has a path to
be consumed, unchecked, by pte_offset_map().
v1 -> v2: Fix typo
---
mm/khugepaged.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 9548644bdb56..1face2ae5877 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -943,6 +943,10 @@ static int hugepage_vma_revalidate(struct mm_struct *mm, unsigned long address,
return SCAN_SUCCEED;
}
+/*
+ * See pmd_trans_unstable() for how the result may change out from
+ * underneath us, even if we hold mmap_lock in read.
+ */
static int find_pmd_or_thp_or_none(struct mm_struct *mm,
unsigned long address,
pmd_t **pmd)
@@ -961,8 +965,12 @@ static int find_pmd_or_thp_or_none(struct mm_struct *mm,
#endif
if (pmd_none(pmde))
return SCAN_PMD_NONE;
+ if (!pmd_present(pmde))
+ return SCAN_PMD_NULL;
if (pmd_trans_huge(pmde))
return SCAN_PMD_MAPPED;
+ if (pmd_devmap(pmde))
+ return SCAN_PMD_NULL;
if (pmd_bad(pmde))
return SCAN_PMD_NULL;
return SCAN_SUCCEED;
--
2.39.1.456.gfc5497dd1b-goog
The patch titled
Subject: mm/MADV_COLLAPSE: catch !none !huge !bad pmd lookups
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
mm-madv_collapse-catch-none-huge-bad-pmd-lookups.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patche…
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: "Zach O'Keefe" <zokeefe(a)google.com>
Subject: mm/MADV_COLLAPSE: catch !none !huge !bad pmd lookups
Date: Wed, 25 Jan 2023 14:53:58 -0800
In commit 34488399fa08 ("mm/madvise: add file and shmem support to
MADV_COLLAPSE") we make the following change to find_pmd_or_thp_or_none():
- if (!pmd_present(pmde))
- return SCAN_PMD_NULL;
+ if (pmd_none(pmde))
+ return SCAN_PMD_NONE;
This was for-use by MADV_COLLAPSE file/shmem codepaths, where
MADV_COLLAPSE might identify a pte-mapped hugepage, only to have
khugepaged race-in, free the pte table, and clear the pmd. Such codepaths
include:
A) If we find a suitably-aligned compound page of order HPAGE_PMD_ORDER
already in the pagecache.
B) In retract_page_tables(), if we fail to grab mmap_lock for the target
mm/address.
In these cases, collapse_pte_mapped_thp() really does expect a none (not
just !present) pmd, and we want to suitably identify that case separate
from the case where no pmd is found, or it's a bad-pmd (of course, many
things could happen once we drop mmap_lock, and the pmd could plausibly
undergo multiple transitions due to intervening fault, split, etc).
Regardless, the code is prepared install a huge-pmd only when the existing
pmd entry is either a genuine pte-table-mapping-pmd, or the none-pmd.
However, the commit introduces a logical hole; namely, that we've allowed
!none- && !huge- && !bad-pmds to be classified as genuine
pte-table-mapping-pmds. One such example that could leak through are swap
entries. The pmd values aren't checked again before use in
pte_offset_map_lock(), which is expecting nothing less than a genuine
pte-table-mapping-pmd.
We want to put back the !pmd_present() check (below the pmd_none() check),
but need to be careful to deal with subtleties in pmd transitions and
treatments by various arch.
The issue is that __split_huge_pmd_locked() temporarily clears the present
bit (or otherwise marks the entry as invalid), but pmd_present() and
pmd_trans_huge() still need to return true while the pmd is in this
transitory state. For example, x86's pmd_present() also checks the
_PAGE_PSE , riscv's version also checks the _PAGE_LEAF bit, and arm64 also
checks a PMD_PRESENT_INVALID bit.
Covering all 4 cases for x86 (all checks done on the same pmd value):
1) pmd_present() && pmd_trans_huge()
All we actually know here is that the PSE bit is set. Either:
a) We aren't racing with __split_huge_page(), and PRESENT or PROTNONE
is set.
=> huge-pmd
b) We are currently racing with __split_huge_page(). The danger here
is that we proceed as-if we have a huge-pmd, but really we are
looking at a pte-mapping-pmd. So, what is the risk of this
danger?
The only relevant path is:
madvise_collapse() -> collapse_pte_mapped_thp()
Where we might just incorrectly report back "success", when really
the memory isn't pmd-backed. This is fine, since split could
happen immediately after (actually) successful madvise_collapse().
So, it should be safe to just assume huge-pmd here.
2) pmd_present() && !pmd_trans_huge()
Either:
a) PSE not set and either PRESENT or PROTNONE is.
=> pte-table-mapping pmd (or PROT_NONE)
b) devmap. This routine can be called immediately after
unlocking/locking mmap_lock -- or called with no locks held (see
khugepaged_scan_mm_slot()), so previous VMA checks have since been
invalidated.
3) !pmd_present() && pmd_trans_huge()
Not possible.
4) !pmd_present() && !pmd_trans_huge()
Neither PRESENT nor PROTNONE set
=> not present
I've checked all archs that implement pmd_trans_huge() (arm64, riscv,
powerpc, longarch, x86, mips, s390) and this logic roughly translates
(though devmap treatment is unique to x86 and powerpc, and (3) doesn't
necessarily hold in general -- but that doesn't matter since
!pmd_present() always takes failure path).
Also, add a comment above find_pmd_or_thp_or_none() to help future
travelers reason about the validity of the code; namely, the possible
mutations that might happen out from under us, depending on how mmap_lock
is held (if at all).
Link: https://lkml.kernel.org/r/20230125225358.2576151-1-zokeefe@google.com
Fixes: 34488399fa08 ("mm/madvise: add file and shmem support to MADV_COLLAPSE")
Signed-off-by: Zach O'Keefe <zokeefe(a)google.com>
Reported-by: Hugh Dickins <hughd(a)google.com>
Cc: Yang Shi <shy828301(a)gmail.com>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
---
--- a/mm/khugepaged.c~mm-madv_collapse-catch-none-huge-bad-pmd-lookups
+++ a/mm/khugepaged.c
@@ -847,6 +847,10 @@ static int hugepage_vma_revalidate(struc
return SCAN_SUCCEED;
}
+/*
+ * See pmd_trans_unstable() for how the result may change out from
+ * underneath us, even if we hold mmap_lock in read.
+ */
static int find_pmd_or_thp_or_none(struct mm_struct *mm,
unsigned long address,
pmd_t **pmd)
@@ -865,8 +869,12 @@ static int find_pmd_or_thp_or_none(struc
#endif
if (pmd_none(pmde))
return SCAN_PMD_NONE;
+ if (!pmd_present(pmde))
+ return SCAN_PMD_NULL;
if (pmd_trans_huge(pmde))
return SCAN_PMD_MAPPED;
+ if (pmd_devmap(pmde))
+ return SCAN_PMD_NULL;
if (pmd_bad(pmde))
return SCAN_PMD_NULL;
return SCAN_SUCCEED;
_
Patches currently in -mm which might be from zokeefe(a)google.com are
mm-madv_collapse-catch-none-huge-bad-pmd-lookups.patch