Re: [RFC PATCH 5/7] riscv: Use pgtable_l4_enabled to output mmu type in cpuinfo

[Alex Ghiti]

On 4/3/20 11:53 AM, Palmer Dabbelt wrote:
> On Sun, 22 Mar 2020 04:00:26 PDT (-0700), alex@xxxxxxxx wrote:
> > Now that the mmu type is determined at runtime using SATP
> > characteristic, use the global variable pgtable_l4_enabled to output
> > mmu type of the processor through /proc/cpuinfo instead of relying on
> > device tree infos.
> >
> > Signed-off-by: Alexandre Ghiti <alex@xxxxxxxx>
> > ---
> > Âarch/riscv/boot/dts/sifive/fu540-c000.dtsi |Â 4 ----
> > Âarch/riscv/kernel/cpu.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ | 24 ++++++++++++----------
> > Â2 files changed, 13 insertions(+), 15 deletions(-)
> >
> > diff --git a/arch/riscv/boot/dts/sifive/fu540-c000.dtsi 
> > b/arch/riscv/boot/dts/sifive/fu540-c000.dtsi
> > index 7db861053483..6138590a2229 100644
> > --- a/arch/riscv/boot/dts/sifive/fu540-c000.dtsi
> > +++ b/arch/riscv/boot/dts/sifive/fu540-c000.dtsi
> > @@ -50,7 +50,6 @@
> > ÂÂÂÂÂÂÂÂÂÂÂÂ i-cache-size = <32768>;
> > ÂÂÂÂÂÂÂÂÂÂÂÂ i-tlb-sets = <1>;
> > ÂÂÂÂÂÂÂÂÂÂÂÂ i-tlb-size = <32>;
> > -ÂÂÂÂÂÂÂÂÂÂÂ mmu-type = "riscv,sv39";
> > ÂÂÂÂÂÂÂÂÂÂÂÂ reg = <1>;
> > ÂÂÂÂÂÂÂÂÂÂÂÂ riscv,isa = "rv64imafdc";
> > ÂÂÂÂÂÂÂÂÂÂÂÂ tlb-split;
> > @@ -74,7 +73,6 @@
> > ÂÂÂÂÂÂÂÂÂÂÂÂ i-cache-size = <32768>;
> > ÂÂÂÂÂÂÂÂÂÂÂÂ i-tlb-sets = <1>;
> > ÂÂÂÂÂÂÂÂÂÂÂÂ i-tlb-size = <32>;
> > -ÂÂÂÂÂÂÂÂÂÂÂ mmu-type = "riscv,sv39";
> > ÂÂÂÂÂÂÂÂÂÂÂÂ reg = <2>;
> > ÂÂÂÂÂÂÂÂÂÂÂÂ riscv,isa = "rv64imafdc";
> > ÂÂÂÂÂÂÂÂÂÂÂÂ tlb-split;
> > @@ -98,7 +96,6 @@
> > ÂÂÂÂÂÂÂÂÂÂÂÂ i-cache-size = <32768>;
> > ÂÂÂÂÂÂÂÂÂÂÂÂ i-tlb-sets = <1>;
> > ÂÂÂÂÂÂÂÂÂÂÂÂ i-tlb-size = <32>;
> > -ÂÂÂÂÂÂÂÂÂÂÂ mmu-type = "riscv,sv39";
> > ÂÂÂÂÂÂÂÂÂÂÂÂ reg = <3>;
> > ÂÂÂÂÂÂÂÂÂÂÂÂ riscv,isa = "rv64imafdc";
> > ÂÂÂÂÂÂÂÂÂÂÂÂ tlb-split;
> > @@ -122,7 +119,6 @@
> > ÂÂÂÂÂÂÂÂÂÂÂÂ i-cache-size = <32768>;
> > ÂÂÂÂÂÂÂÂÂÂÂÂ i-tlb-sets = <1>;
> > ÂÂÂÂÂÂÂÂÂÂÂÂ i-tlb-size = <32>;
> > -ÂÂÂÂÂÂÂÂÂÂÂ mmu-type = "riscv,sv39";
> > ÂÂÂÂÂÂÂÂÂÂÂÂ reg = <4>;
> > ÂÂÂÂÂÂÂÂÂÂÂÂ riscv,isa = "rv64imafdc";
> > ÂÂÂÂÂÂÂÂÂÂÂÂ tlb-split;
> > diff --git a/arch/riscv/kernel/cpu.c b/arch/riscv/kernel/cpu.c
> > index 40a3c442ac5f..38a699b997a8 100644
> > --- a/arch/riscv/kernel/cpu.c
> > +++ b/arch/riscv/kernel/cpu.c
> > @@ -8,6 +8,8 @@
> > Â#include <linux/of.h>
> > Â#include <asm/smp.h>
> >
> > +extern bool pgtable_l4_enabled;
> > +
> > Â/*
> > Â * Returns the hart ID of the given device tree node, or -ENODEV if 
> > the node
> > Â * isn't an enabled and valid RISC-V hart node.
> > @@ -54,18 +56,19 @@ static void print_isa(struct seq_file *f, const 
> > char *isa)
> > ÂÂÂÂ seq_puts(f, "\n");
> > Â}
> >
> > -static void print_mmu(struct seq_file *f, const char *mmu_type)
> > +static void print_mmu(struct seq_file *f)
> > Â{
> > +ÂÂÂ char sv_type[16];
> > +
> > Â#if defined(CONFIG_32BIT)
> > -ÂÂÂ if (strcmp(mmu_type, "riscv,sv32") != 0)
> > -ÂÂÂÂÂÂÂ return;
> > +ÂÂÂ strncpy(sv_type, "sv32", 5);
> > Â#elif defined(CONFIG_64BIT)
> > -ÂÂÂ if (strcmp(mmu_type, "riscv,sv39") != 0 &&
> > -ÂÂÂÂÂÂÂ strcmp(mmu_type, "riscv,sv48") != 0)
> > -ÂÂÂÂÂÂÂ return;
> > +ÂÂÂ if (pgtable_l4_enabled)
> > +ÂÂÂÂÂÂÂ strncpy(sv_type, "sv48", 5);
> > +ÂÂÂ else
> > +ÂÂÂÂÂÂÂ strncpy(sv_type, "sv39", 5);
> > Â#endif
> > -
> > -ÂÂÂ seq_printf(f, "mmu\t\t: %s\n", mmu_type+6);
> > +ÂÂÂ seq_printf(f, "mmu\t\t: %s\n", sv_type);
> > Â}
> >
> > Âstatic void *c_start(struct seq_file *m, loff_t *pos)
> > @@ -90,14 +93,13 @@ static int c_show(struct seq_file *m, void *v)
> > Â{
> > ÂÂÂÂ unsigned long cpu_id = (unsigned long)v - 1;
> > ÂÂÂÂ struct device_node *node = of_get_cpu_node(cpu_id, NULL);
> > -ÂÂÂ const char *compat, *isa, *mmu;
> > +ÂÂÂ const char *compat, *isa;
> >
> > ÂÂÂÂ seq_printf(m, "processor\t: %lu\n", cpu_id);
> > ÂÂÂÂ seq_printf(m, "hart\t\t: %lu\n", cpuid_to_hartid_map(cpu_id));
> > ÂÂÂÂ if (!of_property_read_string(node, "riscv,isa", &isa))
> > ÂÂÂÂÂÂÂÂ print_isa(m, isa);
> > -ÂÂÂ if (!of_property_read_string(node, "mmu-type", &mmu))
> > -ÂÂÂÂÂÂÂ print_mmu(m, mmu);
> > +ÂÂÂ print_mmu(m);
> > ÂÂÂÂ if (!of_property_read_string(node, "compatible", &compat)
> > ÂÂÂÂÂÂÂÂ && strcmp(compat, "riscv"))
> > ÂÂÂÂÂÂÂÂ seq_printf(m, "uarch\t\t: %s\n", compat);
>
> Reviewed-by: Palmer Dabbelt <palmerdabbelt@xxxxxxxxxx>

Thanks,

Alex