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Diffstat (limited to 'results/scraper/launchpad-without-comments/1503031')
| -rw-r--r-- | results/scraper/launchpad-without-comments/1503031 | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/results/scraper/launchpad-without-comments/1503031 b/results/scraper/launchpad-without-comments/1503031 new file mode 100644 index 00000000..e6b41e1a --- /dev/null +++ b/results/scraper/launchpad-without-comments/1503031 @@ -0,0 +1,11 @@ +32-to-64-bit call gate unsupported in IA32e mode + +In particular, the lcall implementation doesn't support the 64-bit TSS. + +helper_lcall_protected (target-i386/seg_helper.c:1884) calls get_ss_esp_from_tss() on a call gate to a lower privilege level, which tries to extract a 32-bit ESP and 16-bit SS from the TSS. In IA32e mode (64-bit or compatibility mode), this instead grabs the lower 32-bits of the target RSP, and 16 of the upper bits as the SS. Additionally, several of the subsequent checks are incorrect (even if the correct stack pointer were extracted). + +This isn't a problem for interrupts since the interrupts are given their own implementation entirely, that uses get_rsp_from_tss() rather than get_ss_esp_from_tss(). + +I believe the missing logic is from the branch starting "ELSE (* current TSS is 64-bit *)" in the CALL pseudocode in the Intel manual (page 3-124 of the PDF I have). + +Reproduced at master (c0b520dfb8890294a9f8879f4759172900585995), and also as of a qemu built a year ago. \ No newline at end of file |