[PowerPC] Fix 32-bit ubldr calling convention
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Authored by bdragon on Jan 19 2020, 3:45 AM.

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rS356878: [PowerPC] Fix 32-bit ubldr calling convention

Summary

Due to the way u-boot for 32-bit powerpc is compiled, the interrupt code assumes that the GOT pointer (r30) on u-boot is always intact.

When making syscalls to u-boot, ensure that we have restored r30 like we found it before we enable interrupts to prevent u-boot from crashing if a timer interrupt was pending.

This fixes ubldr on e500 qemu (assuming you have recompiled qemu's u-boot with API support!)

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rS FreeBSD src repository - subversion

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bdragon created this revision.Jan 19 2020, 3:45 AM

Herald added subscribers: alfredo, luporl, imp. · View Herald TranscriptJan 19 2020, 3:46 AM

jhibbits added inline comments.Jan 19 2020, 3:54 AM

stand/powerpc/uboot/start.S
56	Why did you double the frame size when you only need 4 more bytes?

jhibbits accepted this revision.Jan 19 2020, 4:10 AM

jhibbits added inline comments.

stand/powerpc/uboot/start.S
56	Ah, it's to keep alignment (16-byte alignment is required).

This revision is now accepted and ready to land.Jan 19 2020, 4:10 AM

Closed by commit rS356878: [PowerPC] Fix 32-bit ubldr calling convention (authored by bdragon). · Explain WhyJan 19 2020, 4:13 AM

This revision was automatically updated to reflect the committed changes.

bdragon added a commit: rS356878: [PowerPC] Fix 32-bit ubldr calling convention.

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stand/

powerpc/

uboot/

start.S

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Diff 66987

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stand/powerpc/uboot/start.S

[PowerPC] Fix 32-bit ubldr calling conventionClosedPublicActions