| Message ID | 20230703-greedy-dividable-251fa2b809ac@wendy |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [v3,01/11] RISC-V: Provide a more helpful error message on invalid ISA strings | expand |
On Mon, Jul 03, 2023 at 11:28:03AM +0100, Conor Dooley wrote: > As it says on the tin, provide Kconfig option to control parsing the > "riscv,isa" devicetree property. If either option is used, the kernel > will fall back to parsing "riscv,isa", where "riscv,isa-base" and > "riscv,isa-extensions" are not present. > The Kconfig options are set up so that the default kernel configuration > will enable the fallback path, without needing the commandline option. > > Suggested-by: Andrew Jones <ajones@ventanamicro.com> > Suggested-by: Palmer Dabbelt <palmer@rivosinc.com> > Signed-off-by: Conor Dooley <conor.dooley@microchip.com> > --- > Changes in v3: > - Invert the Kconfig entry. It's now default y & not hidden by > NONPORTABLE, but its entablement will now activate the fallback > - Add a commandline option to enable the fallback on kernels that do not > enable it in Kconfig, as Drew suggested > - Default the global var to the Kconfig option & override it with the > commandline one, rather than have checks for IS_ENABLED() and for the > commandline option in riscv_fill_hwcap() & > riscv_early_of_processor_hartid() My own bot reports a build failure for nommu, because of section mismatches. riscv_early_of_processor_hartid() needs a dose of __init: diff --git a/arch/riscv/kernel/cpu.c b/arch/riscv/kernel/cpu.c index 1acf3679600d..208f1a700121 100644 --- a/arch/riscv/kernel/cpu.c +++ b/arch/riscv/kernel/cpu.c @@ -41,7 +41,7 @@ int riscv_of_processor_hartid(struct device_node *node, unsigned long *hart) return 0; } -int riscv_early_of_processor_hartid(struct device_node *node, unsigned long *hart) +int __init riscv_early_of_processor_hartid(struct device_node *node, unsigned long *hart) { const char *isa; Good aul nommu build, always the one that catches stuff :)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index d910fba25f2c..1bd435f60055 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -5437,6 +5437,13 @@ [KNL] Disable ring 3 MONITOR/MWAIT feature on supported CPUs. + riscv_isa_fallback [RISCV] + When CONFIG_RISCV_ISA_FALLBACK is not enabled, permit + falling back to detecting extension support by parsing + "riscv,isa" property on devicetree systems when the + replacement properties are not found. See the Kconfig + entry for RISCV_ISA_FALLBACK. + ro [KNL] Mount root device read-only on boot rodata= [KNL] diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index 1d39efe2b940..a9a473b67182 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -841,6 +841,24 @@ config XIP_PHYS_ADDR be linked for and stored to. This address is dependent on your own flash usage. +config RISCV_ISA_FALLBACK + bool "Permit falling back to parsing riscv,isa for extension support by default" + default y + help + Parsing the "riscv,isa" devicetree property has been deprecated and + replaced by a list of explicitly defined strings. For compatibility + with existing platforms, the kernel will fall back to parsing the + "riscv,isa" property if the replacements are not found. + + Selecting N here will result in a kernel that does not use the + fallback, unless the commandline "riscv_isa_fallback" parameter is + present. + + Please see the dt-binding, located at + Documentation/devicetree/bindings/riscv/extensions.yaml for details + on the replacement properties of "riscv,isa-base" and + "riscv,isa-extensions". + endmenu # "Boot options" config BUILTIN_DTB diff --git a/arch/riscv/include/asm/hwcap.h b/arch/riscv/include/asm/hwcap.h index e3cda14a486b..b7b58258f6c7 100644 --- a/arch/riscv/include/asm/hwcap.h +++ b/arch/riscv/include/asm/hwcap.h @@ -81,6 +81,7 @@ struct riscv_isa_ext_data { extern const struct riscv_isa_ext_data riscv_isa_ext[]; extern const size_t riscv_isa_ext_count; +extern bool riscv_isa_fallback; unsigned long riscv_isa_extension_base(const unsigned long *isa_bitmap); diff --git a/arch/riscv/kernel/cpu.c b/arch/riscv/kernel/cpu.c index 28d5af21f544..1acf3679600d 100644 --- a/arch/riscv/kernel/cpu.c +++ b/arch/riscv/kernel/cpu.c @@ -87,6 +87,12 @@ int riscv_early_of_processor_hartid(struct device_node *node, unsigned long *har return 0; old_interface: + if (!riscv_isa_fallback) { + pr_warn("CPU with hartid=%lu is invalid: this kernel does not parse \"riscv,isa\"", + *hart); + return -ENODEV; + } + if (of_property_read_string(node, "riscv,isa", &isa)) { pr_warn("CPU with hartid=%lu has no \"riscv,isa-base\" or \"riscv,isa\" property\n", *hart); diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c index 2c4503fa984f..5945dfc5f806 100644 --- a/arch/riscv/kernel/cpufeature.c +++ b/arch/riscv/kernel/cpufeature.c @@ -471,6 +471,18 @@ static int __init riscv_fill_hwcap_from_ext_list(unsigned long *isa2hwcap) return 0; } +#ifdef CONFIG_RISCV_ISA_FALLBACK +bool __initdata riscv_isa_fallback = true; +#else +bool __initdata riscv_isa_fallback; +static int __init riscv_isa_fallback_setup(char *__unused) +{ + riscv_isa_fallback = true; + return 1; +} +early_param("riscv_isa_fallback", riscv_isa_fallback_setup); +#endif + void __init riscv_fill_hwcap(void) { char print_str[NUM_ALPHA_EXTS + 1]; @@ -490,7 +502,7 @@ void __init riscv_fill_hwcap(void) } else { int ret = riscv_fill_hwcap_from_ext_list(isa2hwcap); - if (ret) { + if (ret && riscv_isa_fallback) { pr_info("Falling back to deprecated \"riscv,isa\"\n"); riscv_fill_hwcap_from_isa_string(isa2hwcap); }
As it says on the tin, provide Kconfig option to control parsing the "riscv,isa" devicetree property. If either option is used, the kernel will fall back to parsing "riscv,isa", where "riscv,isa-base" and "riscv,isa-extensions" are not present. The Kconfig options are set up so that the default kernel configuration will enable the fallback path, without needing the commandline option. Suggested-by: Andrew Jones <ajones@ventanamicro.com> Suggested-by: Palmer Dabbelt <palmer@rivosinc.com> Signed-off-by: Conor Dooley <conor.dooley@microchip.com> --- Changes in v3: - Invert the Kconfig entry. It's now default y & not hidden by NONPORTABLE, but its entablement will now activate the fallback - Add a commandline option to enable the fallback on kernels that do not enable it in Kconfig, as Drew suggested - Default the global var to the Kconfig option & override it with the commandline one, rather than have checks for IS_ENABLED() and for the commandline option in riscv_fill_hwcap() & riscv_early_of_processor_hartid() --- .../admin-guide/kernel-parameters.txt | 7 +++++++ arch/riscv/Kconfig | 18 ++++++++++++++++++ arch/riscv/include/asm/hwcap.h | 1 + arch/riscv/kernel/cpu.c | 6 ++++++ arch/riscv/kernel/cpufeature.c | 14 +++++++++++++- 5 files changed, 45 insertions(+), 1 deletion(-)