| Message ID | 20171207172912.17868-3-prarit@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Thu, Dec 7, 2017 at 11:29 AM, Prarit Bhargava <prarit@redhat.com> wrote: > -int __init acpi_parse_spcr(bool earlycon) > +int __init acpi_parse_spcr(bool earlycon, bool enable_console) > { > static char opts[ACPI_SPCR_OPTS_SIZE]; > static char uart[ACPI_SPCR_BUF_SIZE]; > @@ -113,7 +113,8 @@ int __init acpi_parse_spcr(bool earlycon) > if (earlycon) > setup_earlycon(opts); > > - err = add_preferred_console(uart, 0, opts + strlen(uart) + 1); > + if (enable_console) > + err = add_preferred_console(uart, 0, opts + strlen(uart) + 1); So if earlycon==true but enable_console==false, then you parse SPCR and use it for the early console, but not the primary console? I'm not sure what that gives you.
On 12/07/2017 01:46 PM, Timur Tabi wrote: > On Thu, Dec 7, 2017 at 11:29 AM, Prarit Bhargava <prarit@redhat.com> wrote: >> -int __init acpi_parse_spcr(bool earlycon) >> +int __init acpi_parse_spcr(bool earlycon, bool enable_console) >> { >> static char opts[ACPI_SPCR_OPTS_SIZE]; >> static char uart[ACPI_SPCR_BUF_SIZE]; >> @@ -113,7 +113,8 @@ int __init acpi_parse_spcr(bool earlycon) >> if (earlycon) >> setup_earlycon(opts); >> >> - err = add_preferred_console(uart, 0, opts + strlen(uart) + 1); >> + if (enable_console) >> + err = add_preferred_console(uart, 0, opts + strlen(uart) + 1); > > So if earlycon==true but enable_console==false, then you parse SPCR > and use it for the early console, but not the primary console? I'm > not sure what that gives you. > On arm64 the original SPCR code provides both early and primary consoles (as you've pointed out). IOW, if SPRC exists on arm64 a console will be initialized. That is still the case after my change. The expected behaviour on x86 is that unless someone specifies 'earlycon' or 'console=' that no console should be initialized. There are users (some IOT boxes, etc.) that do NOT want a console. The above code keeps the existing x86 behaviour. P.
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 0d173289c67e..c7cc890a0e81 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -918,6 +918,9 @@ stdout-path property in device tree's chosen node, or determined by the ACPI SPCR table. + [X86] When used with no options the early console is + determined by the ACPI SPCR table. + cdns,<addr>[,options] Start an early, polled-mode console on a Cadence (xuartps) serial port at the specified address. Only diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c index ef74e1f3e468..9d7842022d47 100644 --- a/arch/arm64/kernel/acpi.c +++ b/arch/arm64/kernel/acpi.c @@ -355,7 +355,7 @@ void __init acpi_boot_table_init(void) early_init_dt_scan_chosen_stdout(); } else { /* Always enable the ACPI SPCR console */ - acpi_parse_spcr(console_acpi_spcr_enable); + acpi_parse_spcr(console_acpi_spcr_enable, true); if (IS_ENABLED(CONFIG_ACPI_BGRT)) acpi_table_parse(ACPI_SIG_BGRT, acpi_parse_bgrt); } diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c index f4c463df8b08..4527ecbab4cb 100644 --- a/arch/x86/kernel/acpi/boot.c +++ b/arch/x86/kernel/acpi/boot.c @@ -1626,6 +1626,9 @@ int __init acpi_boot_init(void) if (!acpi_noirq) x86_init.pci.init = pci_acpi_init; + /* Do not enable ACPI SPCR console by default */ + acpi_parse_spcr(console_acpi_spcr_enable, console_acpi_spcr_enable); + return 0; } diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig index ae25159dd976..6bcddd149ca7 100644 --- a/drivers/acpi/Kconfig +++ b/drivers/acpi/Kconfig @@ -562,7 +562,7 @@ config TPS68470_PMIC_OPREGION config ACPI_SPCR_TABLE bool "ACPI Serial Port Console Redirection Support" - default y if ARM64 + default y if (X86 || ARM64) help Enable support for Serial Port Console Redirection (SPCR) Table. This table provides information about the configuration of the diff --git a/drivers/acpi/spcr.c b/drivers/acpi/spcr.c index d8ad8fa67582..23abb1c207a0 100644 --- a/drivers/acpi/spcr.c +++ b/drivers/acpi/spcr.c @@ -40,7 +40,7 @@ bool console_acpi_spcr_enable __initdata; * from arch initialization code as soon as the DT/ACPI decision is made. * */ -int __init acpi_parse_spcr(bool earlycon) +int __init acpi_parse_spcr(bool earlycon, bool enable_console) { static char opts[ACPI_SPCR_OPTS_SIZE]; static char uart[ACPI_SPCR_BUF_SIZE]; @@ -113,7 +113,8 @@ int __init acpi_parse_spcr(bool earlycon) if (earlycon) setup_earlycon(opts); - err = add_preferred_console(uart, 0, opts + strlen(uart) + 1); + if (enable_console) + err = add_preferred_console(uart, 0, opts + strlen(uart) + 1); done: acpi_put_table((struct acpi_table_header *)table); return err; diff --git a/include/linux/acpi.h b/include/linux/acpi.h index 818c1053cc6f..252d692f017f 100644 --- a/include/linux/acpi.h +++ b/include/linux/acpi.h @@ -1248,10 +1248,13 @@ extern bool console_acpi_spcr_enable __initdata; extern int acpi_arch_setup_console(struct acpi_table_spcr *table, char *opts, char *uart, char *iotype, int baud_rate, bool earlycon); -int acpi_parse_spcr(bool earlycon); +int acpi_parse_spcr(bool earlycon, bool enable_console); #else static const bool console_acpi_spcr_enable; -static inline int acpi_parse_spcr(bool earlycon) { return 0; } +static inline int acpi_parse_spcr(bool earlycon, bool enable_console) +{ + return 0; +} #endif #if IS_ENABLED(CONFIG_ACPI_GENERIC_GSI)
The ACPI SPCR code has been used to define an earlycon console for arm64 and can be used for x86. Modify the ACPI SPCR parsing code to account for console behaviour differences between arm64 and x86. Initialize the SPCR code from x86 ACPI initialization code. Signed-off-by: Prarit Bhargava <prarit@redhat.com> Cc: linux-doc@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-pm@vger.kernel.org Cc: linux-acpi@vger.kernel.org Cc: linux-serial@vger.kernel.org Cc: Bhupesh Sharma <bhsharma@redhat.com> Cc: Lv Zheng <lv.zheng@intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: x86@kernel.org Cc: Jonathan Corbet <corbet@lwn.net> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> --- Documentation/admin-guide/kernel-parameters.txt | 3 +++ arch/arm64/kernel/acpi.c | 2 +- arch/x86/kernel/acpi/boot.c | 3 +++ drivers/acpi/Kconfig | 2 +- drivers/acpi/spcr.c | 5 +++-- include/linux/acpi.h | 7 +++++-- 6 files changed, 16 insertions(+), 6 deletions(-)