From 8b4eba1d4f41c5e07d2be1de6deb545dee4a2eb1 Mon Sep 17 00:00:00 2001 From: Daniel Bertalan Date: Tue, 25 Apr 2023 11:35:52 +0200 Subject: [PATCH] hw/arm/bcm2835_property: Implement "get command line" message This query copies the kernel command line into the message buffer. It was previously stubbed out to return empty, this commit makes it reflect the arguments specified with `-append`. I observed the following peculiarities on my Pi 3B+: - If the buffer is shorter than the string, the response header gives the full length, but no data is actually copied. - No NUL terminator is added: even if the buffer is long enough to fit one, the buffer's original contents are preserved past the string's end. - The VC firmware adds the following extra parameters beside the user-supplied ones (via /boot/cmdline.txt): `video`, `vc_mem.mem_base` and `vc_mem.mem_size`. This is currently not implemented in qemu. Signed-off-by: Daniel Bertalan --- hw/arm/bcm2835_peripherals.c | 2 ++ hw/arm/bcm2836.c | 2 ++ hw/arm/raspi.c | 2 ++ hw/misc/bcm2835_property.c | 7 ++++++- include/hw/misc/bcm2835_property.h | 1 + 5 files changed, 13 insertions(+), 1 deletion(-) This patch has been submitted upstream: https://lists.nongnu.org/archive/html/qemu-arm/2023-04/msg00549 diff --git a/hw/arm/bcm2835_peripherals.c b/hw/arm/bcm2835_peripherals.c index 3c2a4160cd..0233038b95 100644 --- a/hw/arm/bcm2835_peripherals.c +++ b/hw/arm/bcm2835_peripherals.c @@ -90,6 +90,8 @@ static void bcm2835_peripherals_init(Object *obj) TYPE_BCM2835_PROPERTY); object_property_add_alias(obj, "board-rev", OBJECT(&s->property), "board-rev"); + object_property_add_alias(obj, "command-line", OBJECT(&s->property), + "command-line"); object_property_add_const_link(OBJECT(&s->property), "fb", OBJECT(&s->fb)); diff --git a/hw/arm/bcm2836.c b/hw/arm/bcm2836.c index f894338fc6..166dc896c0 100644 --- a/hw/arm/bcm2836.c +++ b/hw/arm/bcm2836.c @@ -55,6 +55,8 @@ static void bcm2836_init(Object *obj) TYPE_BCM2835_PERIPHERALS); object_property_add_alias(obj, "board-rev", OBJECT(&s->peripherals), "board-rev"); + object_property_add_alias(obj, "command-line", OBJECT(&s->peripherals), + "command-line"); object_property_add_alias(obj, "vcram-size", OBJECT(&s->peripherals), "vcram-size"); } diff --git a/hw/arm/raspi.c b/hw/arm/raspi.c index 92d068d1f9..7b9221c924 100644 --- a/hw/arm/raspi.c +++ b/hw/arm/raspi.c @@ -280,6 +280,8 @@ static void raspi_machine_init(MachineState *machine) object_property_add_const_link(OBJECT(&s->soc), "ram", OBJECT(machine->ram)); object_property_set_int(OBJECT(&s->soc), "board-rev", board_rev, &error_abort); + object_property_set_str(OBJECT(&s->soc), "command-line", + machine->kernel_cmdline, &error_abort); qdev_realize(DEVICE(&s->soc), NULL, &error_fatal); /* Create and plug in the SD cards */ diff --git a/hw/misc/bcm2835_property.c b/hw/misc/bcm2835_property.c index 890ae7bae5..225bce2ba4 100644 --- a/hw/misc/bcm2835_property.c +++ b/hw/misc/bcm2835_property.c @@ -282,7 +282,11 @@ static void bcm2835_property_mbox_push(BCM2835PropertyState *s, uint32_t value) break; case 0x00050001: /* Get command line */ - resplen = 0; + resplen = strlen(s->command_line); + if (bufsize >= resplen) + address_space_write(&s->dma_as, value + 12, + MEMTXATTRS_UNSPECIFIED, s->command_line, + resplen); break; default: @@ -413,6 +417,7 @@ static void bcm2835_property_realize(DeviceState *dev, Error **errp) static Property bcm2835_property_props[] = { DEFINE_PROP_UINT32("board-rev", BCM2835PropertyState, board_rev, 0), + DEFINE_PROP_STRING("command-line", BCM2835PropertyState, command_line), DEFINE_PROP_END_OF_LIST() }; diff --git a/include/hw/misc/bcm2835_property.h b/include/hw/misc/bcm2835_property.h index 712b76b7a3..ba8896610c 100644 --- a/include/hw/misc/bcm2835_property.h +++ b/include/hw/misc/bcm2835_property.h @@ -30,6 +30,7 @@ struct BCM2835PropertyState { MACAddr macaddr; uint32_t board_rev; uint32_t addr; + char *command_line; bool pending; }; -- 2.40.0