* Re: [PATCH] MIPS: ralink: mt7621: do memory detection on KSEG1
2022-02-11 0:13 [PATCH] MIPS: ralink: mt7621: do memory detection on KSEG1 Chuanhong Guo
@ 2022-02-11 1:41 ` Ilya Lipnitskiy
2022-02-11 6:50 ` Sergio Paracuellos
` (3 subsequent siblings)
4 siblings, 0 replies; 8+ messages in thread
From: Ilya Lipnitskiy @ 2022-02-11 1:41 UTC (permalink / raw)
To: Chuanhong Guo
Cc: open list:MIPS, Rui Salvaterra, Thomas Bogendoerfer,
linux-arm-kernel, linux-mediatek, Linux Kernel Mailing List
Hi Guo,
On Thu, Feb 10, 2022 at 4:14 PM Chuanhong Guo <gch981213@gmail.com> wrote:
>
> It's reported that current memory detection code occasionally detects
> larger memory under some bootloaders.
> Current memory detection code tests whether address space wraps around
> on KSEG0, which is unreliable because it's cached.
>
> Rewrite memory size detection to perform the same test on KSEG1 instead.
> While at it, this patch also does the following two things:
> 1. use a fixed pattern instead of a random function pointer as the magic
> value.
> 2. add an additional memory write and a second comparison as part of the
> test to prevent possible smaller memory detection result due to
> leftover values in memory.
>
> Fixes: 139c949f7f0a MIPS: ("ralink: mt7621: add memory detection support")
> Reported-by: Rui Salvaterra <rsalvaterra@gmail.com>
> Signed-off-by: Chuanhong Guo <gch981213@gmail.com>
> ---
> arch/mips/ralink/mt7621.c | 36 +++++++++++++++++++++++-------------
> 1 file changed, 23 insertions(+), 13 deletions(-)
>
> diff --git a/arch/mips/ralink/mt7621.c b/arch/mips/ralink/mt7621.c
> index d6efffd4dd20..12c8808e0dea 100644
> --- a/arch/mips/ralink/mt7621.c
> +++ b/arch/mips/ralink/mt7621.c
> @@ -22,7 +22,9 @@
>
> #include "common.h"
>
> -static void *detect_magic __initdata = detect_memory_region;
> +#define MT7621_MEM_TEST_PATTERN 0xaa5555aa
> +
> +static u32 detect_magic __initdata;
>
> int pcibios_root_bridge_prepare(struct pci_host_bridge *bridge)
> {
> @@ -58,24 +60,32 @@ phys_addr_t mips_cpc_default_phys_base(void)
> panic("Cannot detect cpc address");
> }
>
> +static bool __init mt7621_addr_wraparound_test(phys_addr_t size)
> +{
> + void *dm = (void *)KSEG1ADDR(&detect_magic);
> +
> + if (CPHYSADDR(dm + size) >= MT7621_LOWMEM_MAX_SIZE)
> + return true;
> + __raw_writel(MT7621_MEM_TEST_PATTERN, dm);
> + if (__raw_readl(dm) != __raw_readl(dm + size))
> + return false;
> + __raw_writel(!MT7621_MEM_TEST_PATTERN, dm);
> + return __raw_readl(dm) == __raw_readl(dm + size);
> +}
> +
> static void __init mt7621_memory_detect(void)
> {
> - void *dm = &detect_magic;
> phys_addr_t size;
>
> - for (size = 32 * SZ_1M; size < 256 * SZ_1M; size <<= 1) {
> - if (!__builtin_memcmp(dm, dm + size, sizeof(detect_magic)))
> - break;
> + for (size = 32 * SZ_1M; size <= 256 * SZ_1M; size <<= 1) {
> + if (mt7621_addr_wraparound_test(size)) {
> + memblock_add(MT7621_LOWMEM_BASE, size);
> + return;
> + }
> }
>
> - if ((size == 256 * SZ_1M) &&
> - (CPHYSADDR(dm + size) < MT7621_LOWMEM_MAX_SIZE) &&
> - __builtin_memcmp(dm, dm + size, sizeof(detect_magic))) {
> - memblock_add(MT7621_LOWMEM_BASE, MT7621_LOWMEM_MAX_SIZE);
> - memblock_add(MT7621_HIGHMEM_BASE, MT7621_HIGHMEM_SIZE);
> - } else {
> - memblock_add(MT7621_LOWMEM_BASE, size);
> - }
> + memblock_add(MT7621_LOWMEM_BASE, MT7621_LOWMEM_MAX_SIZE);
> + memblock_add(MT7621_HIGHMEM_BASE, MT7621_HIGHMEM_SIZE);
> }
>
> void __init ralink_of_remap(void)
> --
> 2.34.1
>
Thanks for your change. I think this will also fix
https://lore.kernel.org/lkml/202201191557.OISJHNMi-lkp@intel.com/
since you are removing __builtin_memcmp usage.
Ilya
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH] MIPS: ralink: mt7621: do memory detection on KSEG1
2022-02-11 0:13 [PATCH] MIPS: ralink: mt7621: do memory detection on KSEG1 Chuanhong Guo
2022-02-11 1:41 ` Ilya Lipnitskiy
@ 2022-02-11 6:50 ` Sergio Paracuellos
2022-02-11 8:46 ` Rui Salvaterra
` (2 subsequent siblings)
4 siblings, 0 replies; 8+ messages in thread
From: Sergio Paracuellos @ 2022-02-11 6:50 UTC (permalink / raw)
To: Chuanhong Guo
Cc: open list:MIPS, Rui Salvaterra, Ilya Lipnitskiy,
Thomas Bogendoerfer, linux-arm-kernel,
moderated list:ARM/Mediatek SoC support, linux-kernel
Hi Guo,
On Fri, Feb 11, 2022 at 4:56 AM Chuanhong Guo <gch981213@gmail.com> wrote:
>
> It's reported that current memory detection code occasionally detects
> larger memory under some bootloaders.
> Current memory detection code tests whether address space wraps around
> on KSEG0, which is unreliable because it's cached.
>
> Rewrite memory size detection to perform the same test on KSEG1 instead.
> While at it, this patch also does the following two things:
> 1. use a fixed pattern instead of a random function pointer as the magic
> value.
> 2. add an additional memory write and a second comparison as part of the
> test to prevent possible smaller memory detection result due to
> leftover values in memory.
>
> Fixes: 139c949f7f0a MIPS: ("ralink: mt7621: add memory detection support")
> Reported-by: Rui Salvaterra <rsalvaterra@gmail.com>
> Signed-off-by: Chuanhong Guo <gch981213@gmail.com>
> ---
> arch/mips/ralink/mt7621.c | 36 +++++++++++++++++++++++-------------
> 1 file changed, 23 insertions(+), 13 deletions(-)
Thanks! Nothing seems to be broken after these changes, at least for
my boards :)
Tested-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
Best regards,
Sergio Paracuellos
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH] MIPS: ralink: mt7621: do memory detection on KSEG1
2022-02-11 0:13 [PATCH] MIPS: ralink: mt7621: do memory detection on KSEG1 Chuanhong Guo
2022-02-11 1:41 ` Ilya Lipnitskiy
2022-02-11 6:50 ` Sergio Paracuellos
@ 2022-02-11 8:46 ` Rui Salvaterra
2022-02-15 16:48 ` Chuanhong Guo
2022-02-16 19:54 ` Thomas Bogendoerfer
4 siblings, 0 replies; 8+ messages in thread
From: Rui Salvaterra @ 2022-02-11 8:46 UTC (permalink / raw)
To: Chuanhong Guo
Cc: linux-mips, Ilya Lipnitskiy, Thomas Bogendoerfer,
linux-arm-kernel, linux-mediatek, linux-kernel
Hi, Guo,
On Fri, 11 Feb 2022 at 00:14, Chuanhong Guo <gch981213@gmail.com> wrote:
>
> It's reported that current memory detection code occasionally detects
> larger memory under some bootloaders.
> Current memory detection code tests whether address space wraps around
> on KSEG0, which is unreliable because it's cached.
>
> Rewrite memory size detection to perform the same test on KSEG1 instead.
> While at it, this patch also does the following two things:
> 1. use a fixed pattern instead of a random function pointer as the magic
> value.
> 2. add an additional memory write and a second comparison as part of the
> test to prevent possible smaller memory detection result due to
> leftover values in memory.
[patch snipped]
No issues here, and it does seem to have fixed the RAM size detection
on my Redmi AC2100. It's always been a very sporadic failure here, so
I'll be keeping an eye on it to see if there are any further
misdetections. :)
In any case, feel free to add my
Tested-by: Rui Salvaterra <rsalvaterra@gmail.com>
Thanks,
Rui
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] MIPS: ralink: mt7621: do memory detection on KSEG1
2022-02-11 0:13 [PATCH] MIPS: ralink: mt7621: do memory detection on KSEG1 Chuanhong Guo
` (2 preceding siblings ...)
2022-02-11 8:46 ` Rui Salvaterra
@ 2022-02-15 16:48 ` Chuanhong Guo
2022-02-16 19:54 ` Thomas Bogendoerfer
4 siblings, 0 replies; 8+ messages in thread
From: Chuanhong Guo @ 2022-02-15 16:48 UTC (permalink / raw)
To: linux-mips
Cc: Rui Salvaterra, Ilya Lipnitskiy, Thomas Bogendoerfer,
linux-arm-kernel, linux-mediatek, linux-kernel
Hi!
On Fri, Feb 11, 2022 at 8:14 AM Chuanhong Guo <gch981213@gmail.com> wrote:
>
> It's reported that current memory detection code occasionally detects
> larger memory under some bootloaders.
> Current memory detection code tests whether address space wraps around
> on KSEG0, which is unreliable because it's cached.
>
> Rewrite memory size detection to perform the same test on KSEG1 instead.
> While at it, this patch also does the following two things:
> 1. use a fixed pattern instead of a random function pointer as the magic
> value.
> 2. add an additional memory write and a second comparison as part of the
> test to prevent possible smaller memory detection result due to
> leftover values in memory.
>
> Fixes: 139c949f7f0a MIPS: ("ralink: mt7621: add memory detection support")
I misplaced a bracket in this Fixes tag.
> Reported-by: Rui Salvaterra <rsalvaterra@gmail.com>
> Signed-off-by: Chuanhong Guo <gch981213@gmail.com>
> ---
> arch/mips/ralink/mt7621.c | 36 +++++++++++++++++++++++-------------
> 1 file changed, 23 insertions(+), 13 deletions(-)
>
> diff --git a/arch/mips/ralink/mt7621.c b/arch/mips/ralink/mt7621.c
> index d6efffd4dd20..12c8808e0dea 100644
> --- a/arch/mips/ralink/mt7621.c
> +++ b/arch/mips/ralink/mt7621.c
> @@ -22,7 +22,9 @@
>
> #include "common.h"
>
> -static void *detect_magic __initdata = detect_memory_region;
> +#define MT7621_MEM_TEST_PATTERN 0xaa5555aa
> +
> +static u32 detect_magic __initdata;
>
> int pcibios_root_bridge_prepare(struct pci_host_bridge *bridge)
> {
> @@ -58,24 +60,32 @@ phys_addr_t mips_cpc_default_phys_base(void)
> panic("Cannot detect cpc address");
> }
>
> +static bool __init mt7621_addr_wraparound_test(phys_addr_t size)
> +{
> + void *dm = (void *)KSEG1ADDR(&detect_magic);
> +
> + if (CPHYSADDR(dm + size) >= MT7621_LOWMEM_MAX_SIZE)
> + return true;
> + __raw_writel(MT7621_MEM_TEST_PATTERN, dm);
> + if (__raw_readl(dm) != __raw_readl(dm + size))
> + return false;
> + __raw_writel(!MT7621_MEM_TEST_PATTERN, dm);
Someone on Github notified me that this second test pattern is incorrect.
I actually mean to use ~MT7621_MEM_TEST_PATTERN here.
I'll send a v2 fixing both issues.
--
Regards,
Chuanhong Guo
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH] MIPS: ralink: mt7621: do memory detection on KSEG1
2022-02-11 0:13 [PATCH] MIPS: ralink: mt7621: do memory detection on KSEG1 Chuanhong Guo
` (3 preceding siblings ...)
2022-02-15 16:48 ` Chuanhong Guo
@ 2022-02-16 19:54 ` Thomas Bogendoerfer
2022-02-17 4:06 ` Chuanhong Guo
4 siblings, 1 reply; 8+ messages in thread
From: Thomas Bogendoerfer @ 2022-02-16 19:54 UTC (permalink / raw)
To: Chuanhong Guo
Cc: linux-mips, Rui Salvaterra, Ilya Lipnitskiy, linux-arm-kernel,
linux-mediatek, linux-kernel
On Fri, Feb 11, 2022 at 08:13:44AM +0800, Chuanhong Guo wrote:
> It's reported that current memory detection code occasionally detects
> larger memory under some bootloaders.
> Current memory detection code tests whether address space wraps around
> on KSEG0, which is unreliable because it's cached.
>
> Rewrite memory size detection to perform the same test on KSEG1 instead.
> While at it, this patch also does the following two things:
> 1. use a fixed pattern instead of a random function pointer as the magic
> value.
> 2. add an additional memory write and a second comparison as part of the
> test to prevent possible smaller memory detection result due to
> leftover values in memory.
>
> Fixes: 139c949f7f0a MIPS: ("ralink: mt7621: add memory detection support")
> Reported-by: Rui Salvaterra <rsalvaterra@gmail.com>
> Signed-off-by: Chuanhong Guo <gch981213@gmail.com>
> ---
> arch/mips/ralink/mt7621.c | 36 +++++++++++++++++++++++-------------
> 1 file changed, 23 insertions(+), 13 deletions(-)
applied to mips-fixes.
Thomas.
--
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea. [ RFC1925, 2.3 ]
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH] MIPS: ralink: mt7621: do memory detection on KSEG1
2022-02-16 19:54 ` Thomas Bogendoerfer
@ 2022-02-17 4:06 ` Chuanhong Guo
2022-02-17 7:58 ` Thomas Bogendoerfer
0 siblings, 1 reply; 8+ messages in thread
From: Chuanhong Guo @ 2022-02-17 4:06 UTC (permalink / raw)
To: Thomas Bogendoerfer
Cc: linux-mips, Rui Salvaterra, Ilya Lipnitskiy, linux-arm-kernel,
linux-mediatek, linux-kernel
Hi!
On Thu, Feb 17, 2022 at 3:57 AM Thomas Bogendoerfer
<tsbogend@alpha.franken.de> wrote:
>
> On Fri, Feb 11, 2022 at 08:13:44AM +0800, Chuanhong Guo wrote:
> > It's reported that current memory detection code occasionally detects
> > larger memory under some bootloaders.
> > Current memory detection code tests whether address space wraps around
> > on KSEG0, which is unreliable because it's cached.
> >
> > Rewrite memory size detection to perform the same test on KSEG1 instead.
> > While at it, this patch also does the following two things:
> > 1. use a fixed pattern instead of a random function pointer as the magic
> > value.
> > 2. add an additional memory write and a second comparison as part of the
> > test to prevent possible smaller memory detection result due to
> > leftover values in memory.
> >
> > Fixes: 139c949f7f0a MIPS: ("ralink: mt7621: add memory detection support")
> > Reported-by: Rui Salvaterra <rsalvaterra@gmail.com>
> > Signed-off-by: Chuanhong Guo <gch981213@gmail.com>
> > ---
> > arch/mips/ralink/mt7621.c | 36 +++++++++++++++++++++++-------------
> > 1 file changed, 23 insertions(+), 13 deletions(-)
>
> applied to mips-fixes.
Oops.
As I mentioned in a previous mail, this patch has two cosmetic problems:
1. misplaced bracket in commit message "Fixes" tag
2. incorrect second test pattern: I meant to flip all the bits in the
first pattern,
but I used "!" instead of "~". Any value will work just fine but it
looks weird
to construct a zero using !MT7621_MEM_TEST_PATTERN.
Should I send a second patch to fix this patch or send a v2 of the
original patch?
--
Regards,
Chuanhong Guo
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH] MIPS: ralink: mt7621: do memory detection on KSEG1
2022-02-17 4:06 ` Chuanhong Guo
@ 2022-02-17 7:58 ` Thomas Bogendoerfer
0 siblings, 0 replies; 8+ messages in thread
From: Thomas Bogendoerfer @ 2022-02-17 7:58 UTC (permalink / raw)
To: Chuanhong Guo
Cc: linux-mips, Rui Salvaterra, Ilya Lipnitskiy, linux-arm-kernel,
linux-mediatek, linux-kernel
On Thu, Feb 17, 2022 at 12:06:09PM +0800, Chuanhong Guo wrote:
> Hi!
>
> On Thu, Feb 17, 2022 at 3:57 AM Thomas Bogendoerfer
> <tsbogend@alpha.franken.de> wrote:
> >
> > On Fri, Feb 11, 2022 at 08:13:44AM +0800, Chuanhong Guo wrote:
> > > It's reported that current memory detection code occasionally detects
> > > larger memory under some bootloaders.
> > > Current memory detection code tests whether address space wraps around
> > > on KSEG0, which is unreliable because it's cached.
> > >
> > > Rewrite memory size detection to perform the same test on KSEG1 instead.
> > > While at it, this patch also does the following two things:
> > > 1. use a fixed pattern instead of a random function pointer as the magic
> > > value.
> > > 2. add an additional memory write and a second comparison as part of the
> > > test to prevent possible smaller memory detection result due to
> > > leftover values in memory.
> > >
> > > Fixes: 139c949f7f0a MIPS: ("ralink: mt7621: add memory detection support")
> > > Reported-by: Rui Salvaterra <rsalvaterra@gmail.com>
> > > Signed-off-by: Chuanhong Guo <gch981213@gmail.com>
> > > ---
> > > arch/mips/ralink/mt7621.c | 36 +++++++++++++++++++++++-------------
> > > 1 file changed, 23 insertions(+), 13 deletions(-)
> >
> > applied to mips-fixes.
>
> Oops.
>
> As I mentioned in a previous mail, this patch has two cosmetic problems:
> 1. misplaced bracket in commit message "Fixes" tag
> 2. incorrect second test pattern: I meant to flip all the bits in the
> first pattern,
> but I used "!" instead of "~". Any value will work just fine but it
> looks weird
> to construct a zero using !MT7621_MEM_TEST_PATTERN.
>
> Should I send a second patch to fix this patch or send a v2 of the
> original patch?
a second patch please.
Thomas.
--
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea. [ RFC1925, 2.3 ]
^ permalink raw reply [flat|nested] 8+ messages in thread