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| author | Michael Brown | 2018-03-12 11:55:28 +0100 |
|---|---|---|
| committer | Michael Brown | 2018-03-12 12:02:19 +0100 |
| commit | d8c500b7945e57023dde5bd0be2b0e40963315d9 (patch) | |
| tree | e1303ba73b7dcf7600e3d96b57d4c143d4ea1cc5 | |
| parent | [iscsi] Parse IPv6 address in root path (diff) | |
| download | ipxe-d8c500b7945e57023dde5bd0be2b0e40963315d9.tar.gz ipxe-d8c500b7945e57023dde5bd0be2b0e40963315d9.tar.xz ipxe-d8c500b7945e57023dde5bd0be2b0e40963315d9.zip | |
[efi] Drop to TPL_APPLICATION when gathering entropy
Commit c89a446 ("[efi] Run at TPL_CALLBACK to protect against UEFI
timers") introduced a regression in the EFI entropy gathering code.
When the EFI_RNG_PROTOCOL is not present, we fall back to using timer
interrupts (as for the BIOS build). Since timer interrupts are
disabled at TPL_CALLBACK, WaitForEvent() fails and no entropy can be
gathered.
Fix by dropping to TPL_APPLICATION while entropy gathering is enabled.
Reported-by: Andreas Hammarskjöld <junior@2PintSoftware.com>
Tested-by: Andreas Hammarskjöld <junior@2PintSoftware.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
| -rw-r--r-- | src/interface/efi/efi_entropy.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/src/interface/efi/efi_entropy.c b/src/interface/efi/efi_entropy.c index 881c4c9a..2a2fc905 100644 --- a/src/interface/efi/efi_entropy.c +++ b/src/interface/efi/efi_entropy.c @@ -79,6 +79,9 @@ static int efi_entropy_enable ( void ) { DBGC ( &tick, "ENTROPY %s RNG protocol\n", ( efirng ? "has" : "has no" ) ); + /* Drop to TPL_APPLICATION to allow timer tick event to take place */ + bs->RestoreTPL ( TPL_APPLICATION ); + /* Create timer tick event */ if ( ( efirc = bs->CreateEvent ( EVT_TIMER, TPL_NOTIFY, NULL, NULL, &tick ) ) != 0 ) { @@ -100,6 +103,9 @@ static void efi_entropy_disable ( void ) { /* Close timer tick event */ bs->CloseEvent ( tick ); + + /* Return to TPL_CALLBACK */ + bs->RaiseTPL ( TPL_CALLBACK ); } /** |