Currently, isa string is read and checked for correctness at multiple
places.
Consolidate them into one function and use it only during early bootup.
In case of a incorrect isa string, the cpu shouldn't boot at all.
Signed-off-by: Atish Patra <[email protected]>
---
arch/riscv/include/asm/processor.h | 1 +
arch/riscv/kernel/cpu.c | 41 ++++++++++++++++++++++--------
arch/riscv/kernel/cpufeature.c | 4 +--
arch/riscv/kernel/smpboot.c | 4 +++
4 files changed, 37 insertions(+), 13 deletions(-)
diff --git a/arch/riscv/include/asm/processor.h b/arch/riscv/include/asm/processor.h
index f539149d04c2..189bf98f9a3f 100644
--- a/arch/riscv/include/asm/processor.h
+++ b/arch/riscv/include/asm/processor.h
@@ -74,6 +74,7 @@ static inline void wait_for_interrupt(void)
}
struct device_node;
+int riscv_read_check_isa(struct device_node *node, const char **isa);
int riscv_of_processor_hartid(struct device_node *node);
extern void riscv_fill_hwcap(void);
diff --git a/arch/riscv/kernel/cpu.c b/arch/riscv/kernel/cpu.c
index 40a3c442ac5f..6bd4c7176bf6 100644
--- a/arch/riscv/kernel/cpu.c
+++ b/arch/riscv/kernel/cpu.c
@@ -8,13 +8,43 @@
#include <linux/of.h>
#include <asm/smp.h>
+int riscv_read_check_isa(struct device_node *node, const char **isa)
+{
+ u32 hart;
+
+ if (of_property_read_u32(node, "reg", &hart)) {
+ pr_warn("Found CPU without hart ID\n");
+ return -ENODEV;
+ }
+
+ if (of_property_read_string(node, "riscv,isa", isa)) {
+ pr_warn("CPU with hartid=%d has no \"riscv,isa\" property\n",
+ hart);
+ return -ENODEV;
+ }
+ /*
+ * Linux doesn't support rv32e or rv128i, and we only support booting
+ * kernels on harts with the same ISA that the kernel is compiled for.
+ */
+ if (IS_ENABLED(CONFIG_32BIT) && (strncmp(*isa, "rv32i", 5) != 0)) {
+ pr_warn("hartid=%d has an invalid ISA \"%s\" for 32bit config\n",
+ hart, *isa);
+ return -ENODEV;
+ } else if (IS_ENABLED(CONFIG_64BIT) &&
+ (strncmp(*isa, "rv64i", 5) != 0)) {
+ pr_warn("hartid=%d has an invalid ISA \"%s\" for 64bit config\n",
+ hart, *isa);
+ return -ENODEV;
+ }
+ return 0;
+}
+
/*
* Returns the hart ID of the given device tree node, or -ENODEV if the node
* isn't an enabled and valid RISC-V hart node.
*/
int riscv_of_processor_hartid(struct device_node *node)
{
- const char *isa;
u32 hart;
if (!of_device_is_compatible(node, "riscv")) {
@@ -32,15 +62,6 @@ int riscv_of_processor_hartid(struct device_node *node)
return -ENODEV;
}
- if (of_property_read_string(node, "riscv,isa", &isa)) {
- pr_warn("CPU with hartid=%d has no \"riscv,isa\" property\n", hart);
- return -ENODEV;
- }
- if (isa[0] != 'r' || isa[1] != 'v') {
- pr_warn("CPU with hartid=%d has an invalid ISA of \"%s\"\n", hart, isa);
- return -ENODEV;
- }
-
return hart;
}
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index b1ade9a49347..eaad5aa07403 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -38,10 +38,8 @@ void riscv_fill_hwcap(void)
if (riscv_of_processor_hartid(node) < 0)
continue;
- if (of_property_read_string(node, "riscv,isa", &isa)) {
- pr_warn("Unable to find \"riscv,isa\" devicetree entry\n");
+ if (riscv_read_check_isa(node, &isa) < 0)
continue;
- }
for (i = 0; i < strlen(isa); ++i)
this_hwcap |= isa2hwcap[(unsigned char)(isa[i])];
diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
index 18ae6da5115e..15ee71297abf 100644
--- a/arch/riscv/kernel/smpboot.c
+++ b/arch/riscv/kernel/smpboot.c
@@ -60,12 +60,16 @@ void __init setup_smp(void)
int hart;
bool found_boot_cpu = false;
int cpuid = 1;
+ const char *isa;
for_each_of_cpu_node(dn) {
hart = riscv_of_processor_hartid(dn);
if (hart < 0)
continue;
+ if (riscv_read_check_isa(dn, &isa) < 0)
+ continue;
+
if (hart == cpuid_to_hartid_map(0)) {
BUG_ON(found_boot_cpu);
found_boot_cpu = 1;
--
2.21.0
On Wed, 9 Oct 2019, Atish Patra wrote:
> Currently, isa string is read and checked for correctness at multiple
> places.
>
> Consolidate them into one function and use it only during early bootup.
> In case of a incorrect isa string, the cpu shouldn't boot at all.
>
> Signed-off-by: Atish Patra <[email protected]>
Looks like riscv_read_check_isa() is called twice for each hart. Is there
any way to call it only once per hart?
- Paul
> ---
> arch/riscv/include/asm/processor.h | 1 +
> arch/riscv/kernel/cpu.c | 41 ++++++++++++++++++++++--------
> arch/riscv/kernel/cpufeature.c | 4 +--
> arch/riscv/kernel/smpboot.c | 4 +++
> 4 files changed, 37 insertions(+), 13 deletions(-)
>
> diff --git a/arch/riscv/include/asm/processor.h b/arch/riscv/include/asm/processor.h
> index f539149d04c2..189bf98f9a3f 100644
> --- a/arch/riscv/include/asm/processor.h
> +++ b/arch/riscv/include/asm/processor.h
> @@ -74,6 +74,7 @@ static inline void wait_for_interrupt(void)
> }
>
> struct device_node;
> +int riscv_read_check_isa(struct device_node *node, const char **isa);
> int riscv_of_processor_hartid(struct device_node *node);
>
> extern void riscv_fill_hwcap(void);
> diff --git a/arch/riscv/kernel/cpu.c b/arch/riscv/kernel/cpu.c
> index 40a3c442ac5f..6bd4c7176bf6 100644
> --- a/arch/riscv/kernel/cpu.c
> +++ b/arch/riscv/kernel/cpu.c
> @@ -8,13 +8,43 @@
> #include <linux/of.h>
> #include <asm/smp.h>
>
> +int riscv_read_check_isa(struct device_node *node, const char **isa)
> +{
> + u32 hart;
> +
> + if (of_property_read_u32(node, "reg", &hart)) {
> + pr_warn("Found CPU without hart ID\n");
> + return -ENODEV;
> + }
> +
> + if (of_property_read_string(node, "riscv,isa", isa)) {
> + pr_warn("CPU with hartid=%d has no \"riscv,isa\" property\n",
> + hart);
> + return -ENODEV;
> + }
> + /*
> + * Linux doesn't support rv32e or rv128i, and we only support booting
> + * kernels on harts with the same ISA that the kernel is compiled for.
> + */
> + if (IS_ENABLED(CONFIG_32BIT) && (strncmp(*isa, "rv32i", 5) != 0)) {
> + pr_warn("hartid=%d has an invalid ISA \"%s\" for 32bit config\n",
> + hart, *isa);
> + return -ENODEV;
> + } else if (IS_ENABLED(CONFIG_64BIT) &&
> + (strncmp(*isa, "rv64i", 5) != 0)) {
> + pr_warn("hartid=%d has an invalid ISA \"%s\" for 64bit config\n",
> + hart, *isa);
> + return -ENODEV;
> + }
> + return 0;
> +}
> +
> /*
> * Returns the hart ID of the given device tree node, or -ENODEV if the node
> * isn't an enabled and valid RISC-V hart node.
> */
> int riscv_of_processor_hartid(struct device_node *node)
> {
> - const char *isa;
> u32 hart;
>
> if (!of_device_is_compatible(node, "riscv")) {
> @@ -32,15 +62,6 @@ int riscv_of_processor_hartid(struct device_node *node)
> return -ENODEV;
> }
>
> - if (of_property_read_string(node, "riscv,isa", &isa)) {
> - pr_warn("CPU with hartid=%d has no \"riscv,isa\" property\n", hart);
> - return -ENODEV;
> - }
> - if (isa[0] != 'r' || isa[1] != 'v') {
> - pr_warn("CPU with hartid=%d has an invalid ISA of \"%s\"\n", hart, isa);
> - return -ENODEV;
> - }
> -
> return hart;
> }
>
> diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
> index b1ade9a49347..eaad5aa07403 100644
> --- a/arch/riscv/kernel/cpufeature.c
> +++ b/arch/riscv/kernel/cpufeature.c
> @@ -38,10 +38,8 @@ void riscv_fill_hwcap(void)
> if (riscv_of_processor_hartid(node) < 0)
> continue;
>
> - if (of_property_read_string(node, "riscv,isa", &isa)) {
> - pr_warn("Unable to find \"riscv,isa\" devicetree entry\n");
> + if (riscv_read_check_isa(node, &isa) < 0)
> continue;
> - }
>
> for (i = 0; i < strlen(isa); ++i)
> this_hwcap |= isa2hwcap[(unsigned char)(isa[i])];
> diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
> index 18ae6da5115e..15ee71297abf 100644
> --- a/arch/riscv/kernel/smpboot.c
> +++ b/arch/riscv/kernel/smpboot.c
> @@ -60,12 +60,16 @@ void __init setup_smp(void)
> int hart;
> bool found_boot_cpu = false;
> int cpuid = 1;
> + const char *isa;
>
> for_each_of_cpu_node(dn) {
> hart = riscv_of_processor_hartid(dn);
> if (hart < 0)
> continue;
>
> + if (riscv_read_check_isa(dn, &isa) < 0)
> + continue;
> +
> if (hart == cpuid_to_hartid_map(0)) {
> BUG_ON(found_boot_cpu);
> found_boot_cpu = 1;
> --
> 2.21.0
>
>
- Paul
On Fri, 2019-10-18 at 01:43 -0700, Paul Walmsley wrote:
> On Wed, 9 Oct 2019, Atish Patra wrote:
>
> > Currently, isa string is read and checked for correctness at
> > multiple
> > places.
> >
> > Consolidate them into one function and use it only during early
> > bootup.
> > In case of a incorrect isa string, the cpu shouldn't boot at all.
> >
> > Signed-off-by: Atish Patra <[email protected]>
>
> Looks like riscv_read_check_isa() is called twice for each hart. Is
> there
> any way to call it only once per hart?
>
I had to add the check in riscv_fill_hwcap() because that function is
iterating over all cpu nodes to set the hwcap. Thus, some of the harts
that are not available due to incorrect isa string can affect hwcap.
We can check cpu_possible_mask to figure out the harts with invalid isa
strings but that will perform poorly as RISC-V have more harts in
future.
>
> - Paul
>
> > ---
> > arch/riscv/include/asm/processor.h | 1 +
> > arch/riscv/kernel/cpu.c | 41 ++++++++++++++++++++++--
> > ------
> > arch/riscv/kernel/cpufeature.c | 4 +--
> > arch/riscv/kernel/smpboot.c | 4 +++
> > 4 files changed, 37 insertions(+), 13 deletions(-)
> >
> > diff --git a/arch/riscv/include/asm/processor.h
> > b/arch/riscv/include/asm/processor.h
> > index f539149d04c2..189bf98f9a3f 100644
> > --- a/arch/riscv/include/asm/processor.h
> > +++ b/arch/riscv/include/asm/processor.h
> > @@ -74,6 +74,7 @@ static inline void wait_for_interrupt(void)
> > }
> >
> > struct device_node;
> > +int riscv_read_check_isa(struct device_node *node, const char
> > **isa);
> > int riscv_of_processor_hartid(struct device_node *node);
> >
> > extern void riscv_fill_hwcap(void);
> > diff --git a/arch/riscv/kernel/cpu.c b/arch/riscv/kernel/cpu.c
> > index 40a3c442ac5f..6bd4c7176bf6 100644
> > --- a/arch/riscv/kernel/cpu.c
> > +++ b/arch/riscv/kernel/cpu.c
> > @@ -8,13 +8,43 @@
> > #include <linux/of.h>
> > #include <asm/smp.h>
> >
> > +int riscv_read_check_isa(struct device_node *node, const char
> > **isa)
> > +{
> > + u32 hart;
> > +
> > + if (of_property_read_u32(node, "reg", &hart)) {
> > + pr_warn("Found CPU without hart ID\n");
> > + return -ENODEV;
> > + }
> > +
> > + if (of_property_read_string(node, "riscv,isa", isa)) {
> > + pr_warn("CPU with hartid=%d has no \"riscv,isa\"
> > property\n",
> > + hart);
> > + return -ENODEV;
> > + }
> > + /*
> > + * Linux doesn't support rv32e or rv128i, and we only support
> > booting
> > + * kernels on harts with the same ISA that the kernel is
> > compiled for.
> > + */
> > + if (IS_ENABLED(CONFIG_32BIT) && (strncmp(*isa, "rv32i", 5) !=
> > 0)) {
> > + pr_warn("hartid=%d has an invalid ISA \"%s\" for 32bit
> > config\n",
> > + hart, *isa);
> > + return -ENODEV;
> > + } else if (IS_ENABLED(CONFIG_64BIT) &&
> > + (strncmp(*isa, "rv64i", 5) != 0)) {
> > + pr_warn("hartid=%d has an invalid ISA \"%s\" for 64bit
> > config\n",
> > + hart, *isa);
> > + return -ENODEV;
> > + }
> > + return 0;
> > +}
> > +
> > /*
> > * Returns the hart ID of the given device tree node, or -ENODEV
> > if the node
> > * isn't an enabled and valid RISC-V hart node.
> > */
> > int riscv_of_processor_hartid(struct device_node *node)
> > {
> > - const char *isa;
> > u32 hart;
> >
> > if (!of_device_is_compatible(node, "riscv")) {
> > @@ -32,15 +62,6 @@ int riscv_of_processor_hartid(struct device_node
> > *node)
> > return -ENODEV;
> > }
> >
> > - if (of_property_read_string(node, "riscv,isa", &isa)) {
> > - pr_warn("CPU with hartid=%d has no \"riscv,isa\"
> > property\n", hart);
> > - return -ENODEV;
> > - }
> > - if (isa[0] != 'r' || isa[1] != 'v') {
> > - pr_warn("CPU with hartid=%d has an invalid ISA of
> > \"%s\"\n", hart, isa);
> > - return -ENODEV;
> > - }
> > -
> > return hart;
> > }
> >
> > diff --git a/arch/riscv/kernel/cpufeature.c
> > b/arch/riscv/kernel/cpufeature.c
> > index b1ade9a49347..eaad5aa07403 100644
> > --- a/arch/riscv/kernel/cpufeature.c
> > +++ b/arch/riscv/kernel/cpufeature.c
> > @@ -38,10 +38,8 @@ void riscv_fill_hwcap(void)
> > if (riscv_of_processor_hartid(node) < 0)
> > continue;
> >
> > - if (of_property_read_string(node, "riscv,isa", &isa)) {
> > - pr_warn("Unable to find \"riscv,isa\"
> > devicetree entry\n");
> > + if (riscv_read_check_isa(node, &isa) < 0)
> > continue;
> > - }
> >
> > for (i = 0; i < strlen(isa); ++i)
> > this_hwcap |= isa2hwcap[(unsigned
> > char)(isa[i])];
> > diff --git a/arch/riscv/kernel/smpboot.c
> > b/arch/riscv/kernel/smpboot.c
> > index 18ae6da5115e..15ee71297abf 100644
> > --- a/arch/riscv/kernel/smpboot.c
> > +++ b/arch/riscv/kernel/smpboot.c
> > @@ -60,12 +60,16 @@ void __init setup_smp(void)
> > int hart;
> > bool found_boot_cpu = false;
> > int cpuid = 1;
> > + const char *isa;
> >
> > for_each_of_cpu_node(dn) {
> > hart = riscv_of_processor_hartid(dn);
> > if (hart < 0)
> > continue;
> >
> > + if (riscv_read_check_isa(dn, &isa) < 0)
> > + continue;
> > +
> > if (hart == cpuid_to_hartid_map(0)) {
> > BUG_ON(found_boot_cpu);
> > found_boot_cpu = 1;
> > --
> > 2.21.0
> >
> >
>
> - Paul
>
> _______________________________________________
> linux-riscv mailing list
> [email protected]
> http://lists.infradead.org/mailman/listinfo/linux-riscv
--
Regards,
Atish
On Fri, 18 Oct 2019, Atish Patra wrote:
> On Fri, 2019-10-18 at 01:43 -0700, Paul Walmsley wrote:
> > On Wed, 9 Oct 2019, Atish Patra wrote:
> >
> > > Currently, isa string is read and checked for correctness at
> > > multiple places.
> > >
> > > Consolidate them into one function and use it only during early
> > > bootup. In case of a incorrect isa string, the cpu shouldn't boot at
> > > all.
> > >
> > > Signed-off-by: Atish Patra <[email protected]>
> >
> > Looks like riscv_read_check_isa() is called twice for each hart. Is
> > there any way to call it only once per hart?
> >
>
> I had to add the check in riscv_fill_hwcap() because that function is
> iterating over all cpu nodes to set the hwcap. Thus, some of the harts
> that are not available due to incorrect isa string can affect hwcap.
>
> We can check cpu_possible_mask to figure out the harts with invalid isa
> strings but that will perform poorly as RISC-V have more harts in
> future.
How about just calling riscv_read_check_isa() once for all harts and
leaving riscv_fill_hwcap() the way it was? You'll probably need to hoist
the earlier call out of setup_smp(), so it still is called when
!CONFIG_SMP.
- Paul
On Fri, 2019-10-18 at 11:25 -0700, Paul Walmsley wrote:
> On Fri, 18 Oct 2019, Atish Patra wrote:
>
> > On Fri, 2019-10-18 at 01:43 -0700, Paul Walmsley wrote:
> > > On Wed, 9 Oct 2019, Atish Patra wrote:
> > >
> > > > Currently, isa string is read and checked for correctness at
> > > > multiple places.
> > > >
> > > > Consolidate them into one function and use it only during
> > > > early
> > > > bootup. In case of a incorrect isa string, the cpu shouldn't
> > > > boot at
> > > > all.
> > > >
> > > > Signed-off-by: Atish Patra <[email protected]>
> > >
> > > Looks like riscv_read_check_isa() is called twice for each
> > > hart. Is
> > > there any way to call it only once per hart?
> > >
> >
> > I had to add the check in riscv_fill_hwcap() because that function
> > is
> > iterating over all cpu nodes to set the hwcap. Thus, some of the
> > harts
> > that are not available due to incorrect isa string can affect
> > hwcap.
> >
> > We can check cpu_possible_mask to figure out the harts with invalid
> > isa
> > strings but that will perform poorly as RISC-V have more harts in
> > future.
>
> How about just calling riscv_read_check_isa() once for all harts and
> leaving riscv_fill_hwcap() the way it was?
> You'll probably need to hoist
> the earlier call out of setup_smp(), so it still is called when
> !CONFIG_SMP.
Currently, it doesn't let boot any cpu with incorrect isa string for
smp usecase. We still need to preserve that usecase. I think
setup_smp() use is unavoidable.
If the boot cpu has incorrect isa info for !CONFIG_SMP, I guess we
should halt the boot with BUG_ON. This is a separate
riscv_read_check_isa call with boot hart device node.
This is what we can do:
Maintain a global cpumask of harts with invalid isa strings which would
be set during early bootup (before setup_smp). This cpumask will be
used in setup_smp() and riscv_fill_hwcap() to avoid using harts with
invalid isa. This will make sure that there is only single invocaiton
of riscv_read_check_isa(). In most cases, this cpumask will be empty
and penalty of cpumask check won't matter.
Is that what you had in mind or any other approach to address all 3
usecases ?
>
> - Paul
--
Regards,
Atish