From 996457176bb7c64b3d30996592c754205ec4d3ea Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Mon, 7 Apr 2025 20:22:14 +0300 Subject: [PATCH] x86/early_printk: Use 'mmio32' for consistency, fix comments First of all, using 'mmio' prevents proper implementation of 8-bit accessors. Second, it's simply inconsistent with uart8250 set of options. Rename it to 'mmio32'. While at it, remove rather misleading comment in the documentation. From now on mmio32 is self-explanatory and pciserial supports not only 32-bit MMIO accessors. Also, while at it, fix the comment for the "pciserial" case. The comment seems to be a copy'n'paste error when mentioning "serial" instead of "pciserial" (with double quotes). Fix this. With that, move it upper, so we don't calculate 'buf' twice. Fixes: 3181424aeac2 ("x86/early_printk: Add support for MMIO-based UARTs") Signed-off-by: Andy Shevchenko Signed-off-by: Ingo Molnar Reviewed-by: Denis Mukhin Link: https://lore.kernel.org/r/20250407172214.792745-1-andriy.shevchenko@linux.intel.com --- Documentation/admin-guide/kernel-parameters.txt | 5 +---- arch/x86/kernel/early_printk.c | 10 +++++----- 2 files changed, 6 insertions(+), 9 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 76e538c77e31..d9fd26b95b34 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1407,18 +1407,15 @@ earlyprintk=serial[,0x...[,baudrate]] earlyprintk=ttySn[,baudrate] earlyprintk=dbgp[debugController#] + earlyprintk=mmio32,membase[,{nocfg|baudrate}] earlyprintk=pciserial[,force],bus:device.function[,{nocfg|baudrate}] earlyprintk=xdbc[xhciController#] earlyprintk=bios - earlyprintk=mmio,membase[,{nocfg|baudrate}] earlyprintk is useful when the kernel crashes before the normal console is initialized. It is not enabled by default because it has some cosmetic problems. - Only 32-bit memory addresses are supported for "mmio" - and "pciserial" devices. - Use "nocfg" to skip UART configuration, assume BIOS/firmware has configured UART correctly. diff --git a/arch/x86/kernel/early_printk.c b/arch/x86/kernel/early_printk.c index 611f27e3890c..3aad78bfcb26 100644 --- a/arch/x86/kernel/early_printk.c +++ b/arch/x86/kernel/early_printk.c @@ -389,10 +389,10 @@ static int __init setup_early_printk(char *buf) keep = (strstr(buf, "keep") != NULL); while (*buf != '\0') { - if (!strncmp(buf, "mmio", 4)) { - early_mmio_serial_init(buf + 4); + if (!strncmp(buf, "mmio32", 6)) { + buf += 6; + early_mmio_serial_init(buf); early_console_register(&early_serial_console, keep); - buf += 4; } if (!strncmp(buf, "serial", 6)) { buf += 6; @@ -407,9 +407,9 @@ static int __init setup_early_printk(char *buf) } #ifdef CONFIG_PCI if (!strncmp(buf, "pciserial", 9)) { - early_pci_serial_init(buf + 9); + buf += 9; /* Keep from match the above "pciserial" */ + early_pci_serial_init(buf); early_console_register(&early_serial_console, keep); - buf += 9; /* Keep from match the above "serial" */ } #endif if (!strncmp(buf, "vga", 3) && -- 2.49.0