Use bottom-up ELF placement policy - #1395
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Since now both Linux and OP-TEE shims require bottom-up page placement, the core |
Sangho Lee (sangho2)
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🤖 SemverChecks 🤖 No breaking API changes detected Note: this does not mean API is unchanged, or even that there are no breaking changes; simply, none of the detections triggered. |
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Bring in the two upstream commits on top of 4964033: - df162a1 Relocate page management into dedicated modules (microsoft#1415) - fcad93e Use bottom-up ELF placement policy (microsoft#1395) Resolution: - litebox::mm::linux is now litebox::mm::vmem; every path on our side (including the macOS platform and the shims) follows the rename. - The Linux and Windows userland platforms move prot_flags and their PageManagementProvider impl, with helpers and page tests, into page_mgmt.rs. Our Windows additions (the virtual-memory mutation lock, RecommitCommitted, allocation rollback) move with them unchanged. - The mm test backend gains upstream's Windows TASK_ADDR bounds next to our Apple ones. - Bottom-up ELF placement is ported onto our loader: the main image is claimed from default_low_addr() (which honours the platform's TASK_ADDR_MIN) with MAP_FIXED_NOREPLACE and retried past racing mappings, the interpreter stays top-down, and do_mmap is pub(crate).
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This PR replaces the Linux shim loader's top-down fallback placement policy with a bottom-up policy. Currently, if placement of the main ELF at
DEFAULT_LOW_ADDRfails, the loader searches downward fromTASK_ADDR_MAXfor a suitable gap without accounting for trampoline allocation orbrk-based heap growth. Instead, this PR places the ELF in the first suitable gap at or aboveDEFAULT_LOW_ADDR.