Fix instructions for installting GDB on Fedora

[sirhcel]

The package arm-none-eabi-gdb is no longer provided by Fedora as stated in #364. So let's guide Fedora uses to Other distros then and use a pre-built toolchain provided by ARM. This is also the recommendation from the issue at Fedora.

[rust-highfive]

r? @adamgreig

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[adamgreig]

Thanks!

I suspect Fedora users can probably use gdb-multiarch as well, but the new instructions here should also work fine. Perhaps we should link to a newer version though...

bors merge

[bors]

Build succeeded:

• build-book
• build-chapter (05-led-roulette)
• build-chapter (06-hello-world)
• build-chapter (07-registers)
• build-chapter (08-leds-again)
• build-chapter (09-clocks-and-timers)
• build-chapter (11-usart)
• build-chapter (14-i2c)
• build-chapter (15-led-compass)
• build-chapter (16-punch-o-meter)

[sirhcel]

I suspect Fedora users can probably use gdb-multiarch as well, but the new instructions here should also work fine.

I had a quick look at https://src.fedoraproject.org/projects/rpms/* but it seems that this package is not available.

Perhaps we should link to a newer version though...

Do you mean the version of the toolchain? 10-2020-q4-major is still the latest release according to their website.

[adamgreig]

Huh, I guess no further work required then! I assumed there would have been a 2021 release of the GCC toolchain by now but you're right, there's not, so nothing to update. Thanks for checking!

[hargoniX]

I have been working with Fedora's gdb for the longest time and just using the default package just works ™️ for me:

λ gdb target/thumbv7em-none-eabihf/debug/examples/adc
GNU gdb (GDB) Fedora 10.2-3.fc34
<snip>
Reading symbols from target/thumbv7em-none-eabihf/debug/examples/adc...
(gdb) l main
13      use stm32h7xx_hal::{adc, delay::Delay, pac, prelude::*, rcc::rec::AdcClkSel};
14
15      #[macro_use]
16      mod utilities;
17
18      #[entry]
19      fn main() -> ! {
20          utilities::logger::init();
21          let cp = cortex_m::Peripherals::take().unwrap();
22          let dp = pac::Peripherals::take().unwrap();
(gdb)

My only GDB related packages are:

λ dnf list --installed | grep gdb
gap-pkg-liealgdb.noarch                           2.2.1-4.fc34                           @fedora
gcc-gdb-plugin.x86_64                             11.1.1-3.fc34                          @updates
gdb.x86_64                                        10.2-3.fc34                            @updates
gdb-gdbserver.x86_64                              10.2-3.fc34                            @updates
gdb-headless.x86_64                               10.2-3.fc34                            @updates
gdbm-libs.x86_64                                  1:1.19-2.fc34                          @fedora
wireless-regdb.noarch                             2020.11.20-2.fc34                      @fedora

so it appears to me default fedora gdb just is multiarch already. At least when I run:

(gdb) set architecture
Requires an argument. Valid arguments are i386, i386:x86-64, i386:x64-32, i8086, i386:intel, i386:x86-64:intel, i386:x64-32:intel, s390:64-bit, s390:31-bit, rs6000:6000, rs6000:rs1, rs6000:rsc, rs6000:rs2, powerpc:common64, powerpc:common, powerpc:603, powerpc:EC603e, powerpc:604, powerpc:403, powerpc:601, powerpc:620, powerpc:630, powerpc:a35, powerpc:rs64ii, powerpc:rs64iii, powerpc:7400, powerpc:e500, powerpc:e500mc, powerpc:e500mc64, powerpc:MPC8XX, powerpc:750, powerpc:titan, powerpc:vle, powerpc:e5500, powerpc:e6500, arm, armv2, armv2a, armv3, armv3m, armv4, armv4t, armv5, armv5t, armv5te, xscale, ep9312, iwmmxt, iwmmxt2, armv5tej, armv6, armv6kz, armv6t2, armv6k, armv7, armv6-m, armv6s-m, armv7e-m, armv8-a, armv8-r, armv8-m.base, armv8-m.main, armv8.1-m.main, arm_any, aarch64, aarch64:ilp32, aarch64:armv8-r, auto.
(gdb)

I get quite a lot of architectures