[Bug 59898] New: Wine on aarch64 fails on linux with CONFIG_ARM64_VA_BITS=39

[WineHQ Bugzilla]

http://bugs.winehq.org/show_bug.cgi?id=59898

            Bug ID: 59898
           Summary: Wine on aarch64 fails on linux with
                    CONFIG_ARM64_VA_BITS=39
           Product: Wine
           Version: 8.11
          Hardware: aarch64
                OS: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: loader
          Assignee: [e-mail]
          Reporter: [e-mail]
                CC: [e-mail]
   Regression SHA1: ac1761d1dae8bf114a05e28ed6886deba6c2c860
      Distribution: ---

Since commit ac1761d1dae8bf114a05e28ed6886deba6c2c860, "loader: Build the
preloader as PIE on 64-bit.", Wine on aarch64 fails on linux kernels that are
configured with CONFIG_ARM64_VA_BITS=39.

In my case, old and small SBCs have kernels built with CONFIG_ARM64_VA_BITS=39
(or CONFIG_ARM64_VA_BITS_39=y, which then sets CONFIG_ARM64_VA_BITS to that
value). From
https://github.com/raspberrypi/linux/blob/rpi-6.18.y/arch/arm64/configs/bcm2...,
it seems like even very recent configurations for raspberry pi 4 have this set,
while kernels for raspberry pi 5 are configured with more virtual address bits.

Before ac1761d1dae8bf114a05e28ed6886deba6c2c860, WINEPRELOADER_LDFLAGS
contained "-Wl,-Ttext=0x7d400000". After that commit, if the "-static-pie"
option isn't supported, WINEPRELOADER_LDFLAGS ends up containing
"-Wl,-Ttext=0x7d7d00000000" instead.

I.e. - previously, we set the text section address of 0x7d400000, while we now
set 0x7d7d00000000. The former is a 31 bit address, while the latter is a 47
bit address.

Kernels with CONFIG_ARM64_VA_BITS_39=y just immediately segfault if they try to
execute a binary linked with -Ttext=0x7d7d00000000. Any virtual address with 39
bits or fewer works, while higher addresses won't work.

Reversing the change, setting -Wl,-Ttext=0x7d400000, makes the binaries work
fine (in brief testing) on such aarch64 linux devices. I'm not sure if there's
any immediate drawbacks to it - but I guess it would be nice to set an address
with less than 39 bits, at least for aarch64.

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