Re: [PATCH 2/2] riscv: Use PUD/PGDIR entries for linear mapping when possible
Hi Atish,
Le 6/22/20 à 3:11 PM, Atish Patra a écrit :
On Sun, Jun 21, 2020 at 2:39 AM Alex Ghiti wrote:
Hi Atish,
Le 6/20/20 à 5:04 AM, Alex Ghiti a écrit :
Hi Atish,
Le 6/19/20 à 2:16 PM, Atish Patra a écrit :
On Thu, Jun 18, 2020 at 9:28 PM Alex Ghiti wrote:
Hi Atish,
Le 6/18/20 à 8:47 PM, Atish Patra a écrit :
On Wed, Jun 3, 2020 at 8:38 AM Alexandre Ghiti wrote:
Improve best_map_size so that PUD or PGDIR entries are used for
linear
mapping when possible as it allows better TLB utilization.
Signed-off-by: Alexandre Ghiti
---
arch/riscv/mm/init.c | 45
+---
1 file changed, 34 insertions(+), 11 deletions(-)
diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index 9a5c97e091c1..d275f9f834cf 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -424,13 +424,29 @@ static void __init create_pgd_mapping(pgd_t
*pgdp,
create_pgd_next_mapping(nextp, va, pa, sz, prot);
}
-static uintptr_t __init best_map_size(phys_addr_t base,
phys_addr_t size)
+static bool is_map_size_ok(uintptr_t map_size, phys_addr_t base,
+ uintptr_t base_virt, phys_addr_t size)
{
- /* Upgrade to PMD_SIZE mappings whenever possible */
- if ((base & (PMD_SIZE - 1)) || (size & (PMD_SIZE - 1)))
- return PAGE_SIZE;
+ return !((base & (map_size - 1)) || (base_virt & (map_size
- 1)) ||
+ (size < map_size));
+}
+
+static uintptr_t __init best_map_size(phys_addr_t base, uintptr_t
base_virt,
+ phys_addr_t size)
+{
+#ifndef __PAGETABLE_PMD_FOLDED
+ if (is_map_size_ok(PGDIR_SIZE, base, base_virt, size))
+ return PGDIR_SIZE;
+
+ if (pgtable_l4_enabled)
+ if (is_map_size_ok(PUD_SIZE, base, base_virt, size))
+ return PUD_SIZE;
+#endif
+
+ if (is_map_size_ok(PMD_SIZE, base, base_virt, size))
+ return PMD_SIZE;
- return PMD_SIZE;
+ return PAGE_SIZE;
}
/*
@@ -576,7 +592,7 @@ void create_kernel_page_table(pgd_t *pgdir,
uintptr_t map_size)
asmlinkage void __init setup_vm(uintptr_t dtb_pa)
{
uintptr_t va, end_va;
- uintptr_t map_size = best_map_size(load_pa,
MAX_EARLY_MAPPING_SIZE);
+ uintptr_t map_size;
load_pa = (uintptr_t)(&_start);
load_sz = (uintptr_t)(&_end) - load_pa;
@@ -587,6 +603,7 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa)
kernel_virt_addr = KERNEL_VIRT_ADDR;
+ map_size = best_map_size(load_pa, PAGE_OFFSET,
MAX_EARLY_MAPPING_SIZE);
va_pa_offset = PAGE_OFFSET - load_pa;
va_kernel_pa_offset = kernel_virt_addr - load_pa;
pfn_base = PFN_DOWN(load_pa);
@@ -700,6 +717,8 @@ static void __init setup_vm_final(void)
/* Map all memory banks */
for_each_memblock(memory, reg) {
+ uintptr_t remaining_size;
+
start = reg->base;
end = start + reg->size;
@@ -707,15 +726,19 @@ static void __init setup_vm_final(void)
break;
if (memblock_is_nomap(reg))
continue;
- if (start <= __pa(PAGE_OFFSET) &&
- __pa(PAGE_OFFSET) < end)
- start = __pa(PAGE_OFFSET);
- map_size = best_map_size(start, end - start);
- for (pa = start; pa < end; pa += map_size) {
+ pa = start;
+ remaining_size = reg->size;
+
+ while (remaining_size) {
va = (uintptr_t)__va(pa);
+ map_size = best_map_size(pa, va,
remaining_size);
+
create_pgd_mapping(swapper_pg_dir, va, pa,
map_size, PAGE_KERNEL);
+
+ pa += map_size;
+ remaining_size -= map_size;
}
}
This may not work in the RV32 with 2G memory and if the map_size is
determined to be a page size
for the last memblock. Both pa & remaining_size will overflow and the
loop will try to map memory from zero again.
I'm not sure I understand: if pa starts at 0x8000_ and size is 2G,
then pa will overflow in the last iteration, but remaining_size will
then be equal to 0 right ?
Not unless the remaining_size is at least page size aligned. The last
remaining size would "fff".
It will overflow as well after subtracting the map_size.
While fixing this issue, I noticed that if the size in the device tree
is not aligned on PAGE_SIZE, the size is then automatically realigned on
PAGE_SIZE: see early_init_dt_add_memory_arch where size is and-ed with
PAGE_MASK to remove the unaligned part.
Yes. But the memblock size is not guaranteed to be PAGE_SIZE aligned.
The memblock size is updated in memblock_cap_size
/* adjust *@size so that (@base + *@size) doesn't overflow, return
new size */
Re: [PATCH 2/2] riscv: Use PUD/PGDIR entries for linear mapping when possible
On Sun, Jun 21, 2020 at 2:39 AM Alex Ghiti wrote:
>
> Hi Atish,
>
> Le 6/20/20 à 5:04 AM, Alex Ghiti a écrit :
> > Hi Atish,
> >
> > Le 6/19/20 à 2:16 PM, Atish Patra a écrit :
> >> On Thu, Jun 18, 2020 at 9:28 PM Alex Ghiti wrote:
> >>> Hi Atish,
> >>>
> >>> Le 6/18/20 à 8:47 PM, Atish Patra a écrit :
> On Wed, Jun 3, 2020 at 8:38 AM Alexandre Ghiti wrote:
> > Improve best_map_size so that PUD or PGDIR entries are used for
> > linear
> > mapping when possible as it allows better TLB utilization.
> >
> > Signed-off-by: Alexandre Ghiti
> > ---
> >arch/riscv/mm/init.c | 45
> > +---
> >1 file changed, 34 insertions(+), 11 deletions(-)
> >
> > diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
> > index 9a5c97e091c1..d275f9f834cf 100644
> > --- a/arch/riscv/mm/init.c
> > +++ b/arch/riscv/mm/init.c
> > @@ -424,13 +424,29 @@ static void __init create_pgd_mapping(pgd_t
> > *pgdp,
> > create_pgd_next_mapping(nextp, va, pa, sz, prot);
> >}
> >
> > -static uintptr_t __init best_map_size(phys_addr_t base,
> > phys_addr_t size)
> > +static bool is_map_size_ok(uintptr_t map_size, phys_addr_t base,
> > + uintptr_t base_virt, phys_addr_t size)
> >{
> > - /* Upgrade to PMD_SIZE mappings whenever possible */
> > - if ((base & (PMD_SIZE - 1)) || (size & (PMD_SIZE - 1)))
> > - return PAGE_SIZE;
> > + return !((base & (map_size - 1)) || (base_virt & (map_size
> > - 1)) ||
> > + (size < map_size));
> > +}
> > +
> > +static uintptr_t __init best_map_size(phys_addr_t base, uintptr_t
> > base_virt,
> > + phys_addr_t size)
> > +{
> > +#ifndef __PAGETABLE_PMD_FOLDED
> > + if (is_map_size_ok(PGDIR_SIZE, base, base_virt, size))
> > + return PGDIR_SIZE;
> > +
> > + if (pgtable_l4_enabled)
> > + if (is_map_size_ok(PUD_SIZE, base, base_virt, size))
> > + return PUD_SIZE;
> > +#endif
> > +
> > + if (is_map_size_ok(PMD_SIZE, base, base_virt, size))
> > + return PMD_SIZE;
> >
> > - return PMD_SIZE;
> > + return PAGE_SIZE;
> >}
> >
> >/*
> > @@ -576,7 +592,7 @@ void create_kernel_page_table(pgd_t *pgdir,
> > uintptr_t map_size)
> >asmlinkage void __init setup_vm(uintptr_t dtb_pa)
> >{
> > uintptr_t va, end_va;
> > - uintptr_t map_size = best_map_size(load_pa,
> > MAX_EARLY_MAPPING_SIZE);
> > + uintptr_t map_size;
> >
> > load_pa = (uintptr_t)(&_start);
> > load_sz = (uintptr_t)(&_end) - load_pa;
> > @@ -587,6 +603,7 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa)
> >
> > kernel_virt_addr = KERNEL_VIRT_ADDR;
> >
> > + map_size = best_map_size(load_pa, PAGE_OFFSET,
> > MAX_EARLY_MAPPING_SIZE);
> > va_pa_offset = PAGE_OFFSET - load_pa;
> > va_kernel_pa_offset = kernel_virt_addr - load_pa;
> > pfn_base = PFN_DOWN(load_pa);
> > @@ -700,6 +717,8 @@ static void __init setup_vm_final(void)
> >
> > /* Map all memory banks */
> > for_each_memblock(memory, reg) {
> > + uintptr_t remaining_size;
> > +
> > start = reg->base;
> > end = start + reg->size;
> >
> > @@ -707,15 +726,19 @@ static void __init setup_vm_final(void)
> > break;
> > if (memblock_is_nomap(reg))
> > continue;
> > - if (start <= __pa(PAGE_OFFSET) &&
> > - __pa(PAGE_OFFSET) < end)
> > - start = __pa(PAGE_OFFSET);
> >
> > - map_size = best_map_size(start, end - start);
> > - for (pa = start; pa < end; pa += map_size) {
> > + pa = start;
> > + remaining_size = reg->size;
> > +
> > + while (remaining_size) {
> > va = (uintptr_t)__va(pa);
> > + map_size = best_map_size(pa, va,
> > remaining_size);
> > +
> > create_pgd_mapping(swapper_pg_dir, va, pa,
> > map_size, PAGE_KERNEL);
> > +
> > + pa += map_size;
> > + remaining_size -= map_size;
> > }
> > }
> >
> This may not work in the RV32 with 2G memory and if the map_size is
> determined to be a page size
> for the last memblock. Both pa & remaining_size will overflow and the
> loop
Re: [PATCH 2/2] riscv: Use PUD/PGDIR entries for linear mapping when possible
Hi Atish,
Le 6/20/20 à 5:04 AM, Alex Ghiti a écrit :
Hi Atish,
Le 6/19/20 à 2:16 PM, Atish Patra a écrit :
On Thu, Jun 18, 2020 at 9:28 PM Alex Ghiti wrote:
Hi Atish,
Le 6/18/20 à 8:47 PM, Atish Patra a écrit :
On Wed, Jun 3, 2020 at 8:38 AM Alexandre Ghiti wrote:
Improve best_map_size so that PUD or PGDIR entries are used for
linear
mapping when possible as it allows better TLB utilization.
Signed-off-by: Alexandre Ghiti
---
arch/riscv/mm/init.c | 45
+---
1 file changed, 34 insertions(+), 11 deletions(-)
diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index 9a5c97e091c1..d275f9f834cf 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -424,13 +424,29 @@ static void __init create_pgd_mapping(pgd_t
*pgdp,
create_pgd_next_mapping(nextp, va, pa, sz, prot);
}
-static uintptr_t __init best_map_size(phys_addr_t base,
phys_addr_t size)
+static bool is_map_size_ok(uintptr_t map_size, phys_addr_t base,
+ uintptr_t base_virt, phys_addr_t size)
{
- /* Upgrade to PMD_SIZE mappings whenever possible */
- if ((base & (PMD_SIZE - 1)) || (size & (PMD_SIZE - 1)))
- return PAGE_SIZE;
+ return !((base & (map_size - 1)) || (base_virt & (map_size
- 1)) ||
+ (size < map_size));
+}
+
+static uintptr_t __init best_map_size(phys_addr_t base, uintptr_t
base_virt,
+ phys_addr_t size)
+{
+#ifndef __PAGETABLE_PMD_FOLDED
+ if (is_map_size_ok(PGDIR_SIZE, base, base_virt, size))
+ return PGDIR_SIZE;
+
+ if (pgtable_l4_enabled)
+ if (is_map_size_ok(PUD_SIZE, base, base_virt, size))
+ return PUD_SIZE;
+#endif
+
+ if (is_map_size_ok(PMD_SIZE, base, base_virt, size))
+ return PMD_SIZE;
- return PMD_SIZE;
+ return PAGE_SIZE;
}
/*
@@ -576,7 +592,7 @@ void create_kernel_page_table(pgd_t *pgdir,
uintptr_t map_size)
asmlinkage void __init setup_vm(uintptr_t dtb_pa)
{
uintptr_t va, end_va;
- uintptr_t map_size = best_map_size(load_pa,
MAX_EARLY_MAPPING_SIZE);
+ uintptr_t map_size;
load_pa = (uintptr_t)(&_start);
load_sz = (uintptr_t)(&_end) - load_pa;
@@ -587,6 +603,7 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa)
kernel_virt_addr = KERNEL_VIRT_ADDR;
+ map_size = best_map_size(load_pa, PAGE_OFFSET,
MAX_EARLY_MAPPING_SIZE);
va_pa_offset = PAGE_OFFSET - load_pa;
va_kernel_pa_offset = kernel_virt_addr - load_pa;
pfn_base = PFN_DOWN(load_pa);
@@ -700,6 +717,8 @@ static void __init setup_vm_final(void)
/* Map all memory banks */
for_each_memblock(memory, reg) {
+ uintptr_t remaining_size;
+
start = reg->base;
end = start + reg->size;
@@ -707,15 +726,19 @@ static void __init setup_vm_final(void)
break;
if (memblock_is_nomap(reg))
continue;
- if (start <= __pa(PAGE_OFFSET) &&
- __pa(PAGE_OFFSET) < end)
- start = __pa(PAGE_OFFSET);
- map_size = best_map_size(start, end - start);
- for (pa = start; pa < end; pa += map_size) {
+ pa = start;
+ remaining_size = reg->size;
+
+ while (remaining_size) {
va = (uintptr_t)__va(pa);
+ map_size = best_map_size(pa, va,
remaining_size);
+
create_pgd_mapping(swapper_pg_dir, va, pa,
map_size, PAGE_KERNEL);
+
+ pa += map_size;
+ remaining_size -= map_size;
}
}
This may not work in the RV32 with 2G memory and if the map_size is
determined to be a page size
for the last memblock. Both pa & remaining_size will overflow and the
loop will try to map memory from zero again.
I'm not sure I understand: if pa starts at 0x8000_ and size is 2G,
then pa will overflow in the last iteration, but remaining_size will
then be equal to 0 right ?
Not unless the remaining_size is at least page size aligned. The last
remaining size would "fff".
It will overflow as well after subtracting the map_size.
While fixing this issue, I noticed that if the size in the device tree
is not aligned on PAGE_SIZE, the size is then automatically realigned on
PAGE_SIZE: see early_init_dt_add_memory_arch where size is and-ed with
PAGE_MASK to remove the unaligned part.
So the issue does not need to be fixed :)
Thanks anyway,
Alex
And by the way, I realize that this loop only handles sizes that are
aligned on map_size.
Yeah.
Thanks for noticing, I send a v2.
Alex
Thanks,
Alex
--
2.20.1
Re: [PATCH 2/2] riscv: Use PUD/PGDIR entries for linear mapping when possible
Hi Atish,
Le 6/19/20 à 2:16 PM, Atish Patra a écrit :
On Thu, Jun 18, 2020 at 9:28 PM Alex Ghiti wrote:
Hi Atish,
Le 6/18/20 à 8:47 PM, Atish Patra a écrit :
On Wed, Jun 3, 2020 at 8:38 AM Alexandre Ghiti wrote:
Improve best_map_size so that PUD or PGDIR entries are used for linear
mapping when possible as it allows better TLB utilization.
Signed-off-by: Alexandre Ghiti
---
arch/riscv/mm/init.c | 45 +---
1 file changed, 34 insertions(+), 11 deletions(-)
diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index 9a5c97e091c1..d275f9f834cf 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -424,13 +424,29 @@ static void __init create_pgd_mapping(pgd_t *pgdp,
create_pgd_next_mapping(nextp, va, pa, sz, prot);
}
-static uintptr_t __init best_map_size(phys_addr_t base, phys_addr_t size)
+static bool is_map_size_ok(uintptr_t map_size, phys_addr_t base,
+ uintptr_t base_virt, phys_addr_t size)
{
- /* Upgrade to PMD_SIZE mappings whenever possible */
- if ((base & (PMD_SIZE - 1)) || (size & (PMD_SIZE - 1)))
- return PAGE_SIZE;
+ return !((base & (map_size - 1)) || (base_virt & (map_size - 1)) ||
+ (size < map_size));
+}
+
+static uintptr_t __init best_map_size(phys_addr_t base, uintptr_t base_virt,
+ phys_addr_t size)
+{
+#ifndef __PAGETABLE_PMD_FOLDED
+ if (is_map_size_ok(PGDIR_SIZE, base, base_virt, size))
+ return PGDIR_SIZE;
+
+ if (pgtable_l4_enabled)
+ if (is_map_size_ok(PUD_SIZE, base, base_virt, size))
+ return PUD_SIZE;
+#endif
+
+ if (is_map_size_ok(PMD_SIZE, base, base_virt, size))
+ return PMD_SIZE;
- return PMD_SIZE;
+ return PAGE_SIZE;
}
/*
@@ -576,7 +592,7 @@ void create_kernel_page_table(pgd_t *pgdir, uintptr_t
map_size)
asmlinkage void __init setup_vm(uintptr_t dtb_pa)
{
uintptr_t va, end_va;
- uintptr_t map_size = best_map_size(load_pa, MAX_EARLY_MAPPING_SIZE);
+ uintptr_t map_size;
load_pa = (uintptr_t)(&_start);
load_sz = (uintptr_t)(&_end) - load_pa;
@@ -587,6 +603,7 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa)
kernel_virt_addr = KERNEL_VIRT_ADDR;
+ map_size = best_map_size(load_pa, PAGE_OFFSET, MAX_EARLY_MAPPING_SIZE);
va_pa_offset = PAGE_OFFSET - load_pa;
va_kernel_pa_offset = kernel_virt_addr - load_pa;
pfn_base = PFN_DOWN(load_pa);
@@ -700,6 +717,8 @@ static void __init setup_vm_final(void)
/* Map all memory banks */
for_each_memblock(memory, reg) {
+ uintptr_t remaining_size;
+
start = reg->base;
end = start + reg->size;
@@ -707,15 +726,19 @@ static void __init setup_vm_final(void)
break;
if (memblock_is_nomap(reg))
continue;
- if (start <= __pa(PAGE_OFFSET) &&
- __pa(PAGE_OFFSET) < end)
- start = __pa(PAGE_OFFSET);
- map_size = best_map_size(start, end - start);
- for (pa = start; pa < end; pa += map_size) {
+ pa = start;
+ remaining_size = reg->size;
+
+ while (remaining_size) {
va = (uintptr_t)__va(pa);
+ map_size = best_map_size(pa, va, remaining_size);
+
create_pgd_mapping(swapper_pg_dir, va, pa,
map_size, PAGE_KERNEL);
+
+ pa += map_size;
+ remaining_size -= map_size;
}
}
This may not work in the RV32 with 2G memory and if the map_size is
determined to be a page size
for the last memblock. Both pa & remaining_size will overflow and the
loop will try to map memory from zero again.
I'm not sure I understand: if pa starts at 0x8000_ and size is 2G,
then pa will overflow in the last iteration, but remaining_size will
then be equal to 0 right ?
Not unless the remaining_size is at least page size aligned. The last
remaining size would "fff".
It will overflow as well after subtracting the map_size.
And by the way, I realize that this loop only handles sizes that are
aligned on map_size.
Yeah.
Thanks for noticing, I send a v2.
Alex
Thanks,
Alex
--
2.20.1
Re: [PATCH 2/2] riscv: Use PUD/PGDIR entries for linear mapping when possible
On Thu, Jun 18, 2020 at 9:28 PM Alex Ghiti wrote:
>
> Hi Atish,
>
> Le 6/18/20 à 8:47 PM, Atish Patra a écrit :
> > On Wed, Jun 3, 2020 at 8:38 AM Alexandre Ghiti wrote:
> >> Improve best_map_size so that PUD or PGDIR entries are used for linear
> >> mapping when possible as it allows better TLB utilization.
> >>
> >> Signed-off-by: Alexandre Ghiti
> >> ---
> >> arch/riscv/mm/init.c | 45 +---
> >> 1 file changed, 34 insertions(+), 11 deletions(-)
> >>
> >> diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
> >> index 9a5c97e091c1..d275f9f834cf 100644
> >> --- a/arch/riscv/mm/init.c
> >> +++ b/arch/riscv/mm/init.c
> >> @@ -424,13 +424,29 @@ static void __init create_pgd_mapping(pgd_t *pgdp,
> >> create_pgd_next_mapping(nextp, va, pa, sz, prot);
> >> }
> >>
> >> -static uintptr_t __init best_map_size(phys_addr_t base, phys_addr_t size)
> >> +static bool is_map_size_ok(uintptr_t map_size, phys_addr_t base,
> >> + uintptr_t base_virt, phys_addr_t size)
> >> {
> >> - /* Upgrade to PMD_SIZE mappings whenever possible */
> >> - if ((base & (PMD_SIZE - 1)) || (size & (PMD_SIZE - 1)))
> >> - return PAGE_SIZE;
> >> + return !((base & (map_size - 1)) || (base_virt & (map_size - 1)) ||
> >> + (size < map_size));
> >> +}
> >> +
> >> +static uintptr_t __init best_map_size(phys_addr_t base, uintptr_t
> >> base_virt,
> >> + phys_addr_t size)
> >> +{
> >> +#ifndef __PAGETABLE_PMD_FOLDED
> >> + if (is_map_size_ok(PGDIR_SIZE, base, base_virt, size))
> >> + return PGDIR_SIZE;
> >> +
> >> + if (pgtable_l4_enabled)
> >> + if (is_map_size_ok(PUD_SIZE, base, base_virt, size))
> >> + return PUD_SIZE;
> >> +#endif
> >> +
> >> + if (is_map_size_ok(PMD_SIZE, base, base_virt, size))
> >> + return PMD_SIZE;
> >>
> >> - return PMD_SIZE;
> >> + return PAGE_SIZE;
> >> }
> >>
> >> /*
> >> @@ -576,7 +592,7 @@ void create_kernel_page_table(pgd_t *pgdir, uintptr_t
> >> map_size)
> >> asmlinkage void __init setup_vm(uintptr_t dtb_pa)
> >> {
> >> uintptr_t va, end_va;
> >> - uintptr_t map_size = best_map_size(load_pa,
> >> MAX_EARLY_MAPPING_SIZE);
> >> + uintptr_t map_size;
> >>
> >> load_pa = (uintptr_t)(&_start);
> >> load_sz = (uintptr_t)(&_end) - load_pa;
> >> @@ -587,6 +603,7 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa)
> >>
> >> kernel_virt_addr = KERNEL_VIRT_ADDR;
> >>
> >> + map_size = best_map_size(load_pa, PAGE_OFFSET,
> >> MAX_EARLY_MAPPING_SIZE);
> >> va_pa_offset = PAGE_OFFSET - load_pa;
> >> va_kernel_pa_offset = kernel_virt_addr - load_pa;
> >> pfn_base = PFN_DOWN(load_pa);
> >> @@ -700,6 +717,8 @@ static void __init setup_vm_final(void)
> >>
> >> /* Map all memory banks */
> >> for_each_memblock(memory, reg) {
> >> + uintptr_t remaining_size;
> >> +
> >> start = reg->base;
> >> end = start + reg->size;
> >>
> >> @@ -707,15 +726,19 @@ static void __init setup_vm_final(void)
> >> break;
> >> if (memblock_is_nomap(reg))
> >> continue;
> >> - if (start <= __pa(PAGE_OFFSET) &&
> >> - __pa(PAGE_OFFSET) < end)
> >> - start = __pa(PAGE_OFFSET);
> >>
> >> - map_size = best_map_size(start, end - start);
> >> - for (pa = start; pa < end; pa += map_size) {
> >> + pa = start;
> >> + remaining_size = reg->size;
> >> +
> >> + while (remaining_size) {
> >> va = (uintptr_t)__va(pa);
> >> + map_size = best_map_size(pa, va, remaining_size);
> >> +
> >> create_pgd_mapping(swapper_pg_dir, va, pa,
> >> map_size, PAGE_KERNEL);
> >> +
> >> + pa += map_size;
> >> + remaining_size -= map_size;
> >> }
> >> }
> >>
> > This may not work in the RV32 with 2G memory and if the map_size is
> > determined to be a page size
> > for the last memblock. Both pa & remaining_size will overflow and the
> > loop will try to map memory from zero again.
>
> I'm not sure I understand: if pa starts at 0x8000_ and size is 2G,
> then pa will overflow in the last iteration, but remaining_size will
> then be equal to 0 right ?
>
Not unless the remaining_size is at least page size aligned. The last
remaining size would "fff".
It will overflow as well after subtracting the map_size.
> And by the way, I realize that this loop only handles sizes that are
> aligned on map_size.
>
Yeah.
> Thanks,
>
> Alex
>
>
> >
> >> --
> >> 2.20.1
> >>
> >>
> >
--
Regards,
Atish
Re: [PATCH 2/2] riscv: Use PUD/PGDIR entries for linear mapping when possible
Hi Atish,
Le 6/18/20 à 8:47 PM, Atish Patra a écrit :
On Wed, Jun 3, 2020 at 8:38 AM Alexandre Ghiti wrote:
Improve best_map_size so that PUD or PGDIR entries are used for linear
mapping when possible as it allows better TLB utilization.
Signed-off-by: Alexandre Ghiti
---
arch/riscv/mm/init.c | 45 +---
1 file changed, 34 insertions(+), 11 deletions(-)
diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index 9a5c97e091c1..d275f9f834cf 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -424,13 +424,29 @@ static void __init create_pgd_mapping(pgd_t *pgdp,
create_pgd_next_mapping(nextp, va, pa, sz, prot);
}
-static uintptr_t __init best_map_size(phys_addr_t base, phys_addr_t size)
+static bool is_map_size_ok(uintptr_t map_size, phys_addr_t base,
+ uintptr_t base_virt, phys_addr_t size)
{
- /* Upgrade to PMD_SIZE mappings whenever possible */
- if ((base & (PMD_SIZE - 1)) || (size & (PMD_SIZE - 1)))
- return PAGE_SIZE;
+ return !((base & (map_size - 1)) || (base_virt & (map_size - 1)) ||
+ (size < map_size));
+}
+
+static uintptr_t __init best_map_size(phys_addr_t base, uintptr_t base_virt,
+ phys_addr_t size)
+{
+#ifndef __PAGETABLE_PMD_FOLDED
+ if (is_map_size_ok(PGDIR_SIZE, base, base_virt, size))
+ return PGDIR_SIZE;
+
+ if (pgtable_l4_enabled)
+ if (is_map_size_ok(PUD_SIZE, base, base_virt, size))
+ return PUD_SIZE;
+#endif
+
+ if (is_map_size_ok(PMD_SIZE, base, base_virt, size))
+ return PMD_SIZE;
- return PMD_SIZE;
+ return PAGE_SIZE;
}
/*
@@ -576,7 +592,7 @@ void create_kernel_page_table(pgd_t *pgdir, uintptr_t
map_size)
asmlinkage void __init setup_vm(uintptr_t dtb_pa)
{
uintptr_t va, end_va;
- uintptr_t map_size = best_map_size(load_pa, MAX_EARLY_MAPPING_SIZE);
+ uintptr_t map_size;
load_pa = (uintptr_t)(&_start);
load_sz = (uintptr_t)(&_end) - load_pa;
@@ -587,6 +603,7 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa)
kernel_virt_addr = KERNEL_VIRT_ADDR;
+ map_size = best_map_size(load_pa, PAGE_OFFSET, MAX_EARLY_MAPPING_SIZE);
va_pa_offset = PAGE_OFFSET - load_pa;
va_kernel_pa_offset = kernel_virt_addr - load_pa;
pfn_base = PFN_DOWN(load_pa);
@@ -700,6 +717,8 @@ static void __init setup_vm_final(void)
/* Map all memory banks */
for_each_memblock(memory, reg) {
+ uintptr_t remaining_size;
+
start = reg->base;
end = start + reg->size;
@@ -707,15 +726,19 @@ static void __init setup_vm_final(void)
break;
if (memblock_is_nomap(reg))
continue;
- if (start <= __pa(PAGE_OFFSET) &&
- __pa(PAGE_OFFSET) < end)
- start = __pa(PAGE_OFFSET);
- map_size = best_map_size(start, end - start);
- for (pa = start; pa < end; pa += map_size) {
+ pa = start;
+ remaining_size = reg->size;
+
+ while (remaining_size) {
va = (uintptr_t)__va(pa);
+ map_size = best_map_size(pa, va, remaining_size);
+
create_pgd_mapping(swapper_pg_dir, va, pa,
map_size, PAGE_KERNEL);
+
+ pa += map_size;
+ remaining_size -= map_size;
}
}
This may not work in the RV32 with 2G memory and if the map_size is
determined to be a page size
for the last memblock. Both pa & remaining_size will overflow and the
loop will try to map memory from zero again.
I'm not sure I understand: if pa starts at 0x8000_ and size is 2G,
then pa will overflow in the last iteration, but remaining_size will
then be equal to 0 right ?
And by the way, I realize that this loop only handles sizes that are
aligned on map_size.
Thanks,
Alex
--
2.20.1
Re: [PATCH 2/2] riscv: Use PUD/PGDIR entries for linear mapping when possible
On Wed, Jun 3, 2020 at 8:38 AM Alexandre Ghiti wrote:
>
> Improve best_map_size so that PUD or PGDIR entries are used for linear
> mapping when possible as it allows better TLB utilization.
>
> Signed-off-by: Alexandre Ghiti
> ---
> arch/riscv/mm/init.c | 45 +---
> 1 file changed, 34 insertions(+), 11 deletions(-)
>
> diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
> index 9a5c97e091c1..d275f9f834cf 100644
> --- a/arch/riscv/mm/init.c
> +++ b/arch/riscv/mm/init.c
> @@ -424,13 +424,29 @@ static void __init create_pgd_mapping(pgd_t *pgdp,
> create_pgd_next_mapping(nextp, va, pa, sz, prot);
> }
>
> -static uintptr_t __init best_map_size(phys_addr_t base, phys_addr_t size)
> +static bool is_map_size_ok(uintptr_t map_size, phys_addr_t base,
> + uintptr_t base_virt, phys_addr_t size)
> {
> - /* Upgrade to PMD_SIZE mappings whenever possible */
> - if ((base & (PMD_SIZE - 1)) || (size & (PMD_SIZE - 1)))
> - return PAGE_SIZE;
> + return !((base & (map_size - 1)) || (base_virt & (map_size - 1)) ||
> + (size < map_size));
> +}
> +
> +static uintptr_t __init best_map_size(phys_addr_t base, uintptr_t base_virt,
> + phys_addr_t size)
> +{
> +#ifndef __PAGETABLE_PMD_FOLDED
> + if (is_map_size_ok(PGDIR_SIZE, base, base_virt, size))
> + return PGDIR_SIZE;
> +
> + if (pgtable_l4_enabled)
> + if (is_map_size_ok(PUD_SIZE, base, base_virt, size))
> + return PUD_SIZE;
> +#endif
> +
> + if (is_map_size_ok(PMD_SIZE, base, base_virt, size))
> + return PMD_SIZE;
>
> - return PMD_SIZE;
> + return PAGE_SIZE;
> }
>
> /*
> @@ -576,7 +592,7 @@ void create_kernel_page_table(pgd_t *pgdir, uintptr_t
> map_size)
> asmlinkage void __init setup_vm(uintptr_t dtb_pa)
> {
> uintptr_t va, end_va;
> - uintptr_t map_size = best_map_size(load_pa, MAX_EARLY_MAPPING_SIZE);
> + uintptr_t map_size;
>
> load_pa = (uintptr_t)(&_start);
> load_sz = (uintptr_t)(&_end) - load_pa;
> @@ -587,6 +603,7 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa)
>
> kernel_virt_addr = KERNEL_VIRT_ADDR;
>
> + map_size = best_map_size(load_pa, PAGE_OFFSET,
> MAX_EARLY_MAPPING_SIZE);
> va_pa_offset = PAGE_OFFSET - load_pa;
> va_kernel_pa_offset = kernel_virt_addr - load_pa;
> pfn_base = PFN_DOWN(load_pa);
> @@ -700,6 +717,8 @@ static void __init setup_vm_final(void)
>
> /* Map all memory banks */
> for_each_memblock(memory, reg) {
> + uintptr_t remaining_size;
> +
> start = reg->base;
> end = start + reg->size;
>
> @@ -707,15 +726,19 @@ static void __init setup_vm_final(void)
> break;
> if (memblock_is_nomap(reg))
> continue;
> - if (start <= __pa(PAGE_OFFSET) &&
> - __pa(PAGE_OFFSET) < end)
> - start = __pa(PAGE_OFFSET);
>
> - map_size = best_map_size(start, end - start);
> - for (pa = start; pa < end; pa += map_size) {
> + pa = start;
> + remaining_size = reg->size;
> +
> + while (remaining_size) {
> va = (uintptr_t)__va(pa);
> + map_size = best_map_size(pa, va, remaining_size);
> +
> create_pgd_mapping(swapper_pg_dir, va, pa,
>map_size, PAGE_KERNEL);
> +
> + pa += map_size;
> + remaining_size -= map_size;
> }
> }
>
This may not work in the RV32 with 2G memory and if the map_size is
determined to be a page size
for the last memblock. Both pa & remaining_size will overflow and the
loop will try to map memory from zero again.
> --
> 2.20.1
>
>
--
Regards,
Atish
[PATCH 2/2] riscv: Use PUD/PGDIR entries for linear mapping when possible
Improve best_map_size so that PUD or PGDIR entries are used for linear
mapping when possible as it allows better TLB utilization.
Signed-off-by: Alexandre Ghiti
---
arch/riscv/mm/init.c | 45 +---
1 file changed, 34 insertions(+), 11 deletions(-)
diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index 9a5c97e091c1..d275f9f834cf 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -424,13 +424,29 @@ static void __init create_pgd_mapping(pgd_t *pgdp,
create_pgd_next_mapping(nextp, va, pa, sz, prot);
}
-static uintptr_t __init best_map_size(phys_addr_t base, phys_addr_t size)
+static bool is_map_size_ok(uintptr_t map_size, phys_addr_t base,
+ uintptr_t base_virt, phys_addr_t size)
{
- /* Upgrade to PMD_SIZE mappings whenever possible */
- if ((base & (PMD_SIZE - 1)) || (size & (PMD_SIZE - 1)))
- return PAGE_SIZE;
+ return !((base & (map_size - 1)) || (base_virt & (map_size - 1)) ||
+ (size < map_size));
+}
+
+static uintptr_t __init best_map_size(phys_addr_t base, uintptr_t base_virt,
+ phys_addr_t size)
+{
+#ifndef __PAGETABLE_PMD_FOLDED
+ if (is_map_size_ok(PGDIR_SIZE, base, base_virt, size))
+ return PGDIR_SIZE;
+
+ if (pgtable_l4_enabled)
+ if (is_map_size_ok(PUD_SIZE, base, base_virt, size))
+ return PUD_SIZE;
+#endif
+
+ if (is_map_size_ok(PMD_SIZE, base, base_virt, size))
+ return PMD_SIZE;
- return PMD_SIZE;
+ return PAGE_SIZE;
}
/*
@@ -576,7 +592,7 @@ void create_kernel_page_table(pgd_t *pgdir, uintptr_t
map_size)
asmlinkage void __init setup_vm(uintptr_t dtb_pa)
{
uintptr_t va, end_va;
- uintptr_t map_size = best_map_size(load_pa, MAX_EARLY_MAPPING_SIZE);
+ uintptr_t map_size;
load_pa = (uintptr_t)(&_start);
load_sz = (uintptr_t)(&_end) - load_pa;
@@ -587,6 +603,7 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa)
kernel_virt_addr = KERNEL_VIRT_ADDR;
+ map_size = best_map_size(load_pa, PAGE_OFFSET, MAX_EARLY_MAPPING_SIZE);
va_pa_offset = PAGE_OFFSET - load_pa;
va_kernel_pa_offset = kernel_virt_addr - load_pa;
pfn_base = PFN_DOWN(load_pa);
@@ -700,6 +717,8 @@ static void __init setup_vm_final(void)
/* Map all memory banks */
for_each_memblock(memory, reg) {
+ uintptr_t remaining_size;
+
start = reg->base;
end = start + reg->size;
@@ -707,15 +726,19 @@ static void __init setup_vm_final(void)
break;
if (memblock_is_nomap(reg))
continue;
- if (start <= __pa(PAGE_OFFSET) &&
- __pa(PAGE_OFFSET) < end)
- start = __pa(PAGE_OFFSET);
- map_size = best_map_size(start, end - start);
- for (pa = start; pa < end; pa += map_size) {
+ pa = start;
+ remaining_size = reg->size;
+
+ while (remaining_size) {
va = (uintptr_t)__va(pa);
+ map_size = best_map_size(pa, va, remaining_size);
+
create_pgd_mapping(swapper_pg_dir, va, pa,
map_size, PAGE_KERNEL);
+
+ pa += map_size;
+ remaining_size -= map_size;
}
}
--
2.20.1
